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UNDERFLOOR HEATINGA solution or a problem?
Joakim Larsson
Master Thesis in Energy-efficient and Environmental BuildingsFaculty of Engineering | Lund University
Lund UniversityLund University, with eight faculties and a number of research centers and specialized institutes, is the largest establishment for research and higher education in Scandinavia. The main part of the University is situated in the small city of Lund which has about 112 000 inhabitants. A number of departments for research and education are, however, located in Malmö and Helsingborg. Lund University was founded in 1666 and has today a total staff of 6 000 employees and 47 000 students attending 280 degree programs and 2 300 subject courses offered by 63 departments.
Master Program in Energy-efficient and Environmental Building DesignThis international program provides knowledge, skills and competencies within the area of energy-efficient and environmental building design in cold climates. The goal is to train highly skilled professionals, who will significantly contribute to and influence the design, building or renovation of energy-efficient buildings, taking into consideration the architecture and environment, the inhabitantsâ behavior and needs, their health and comfort as well as the overall economy.
The degree project is the final part of the master program leading to a Master of Science (120 credits) in Energy-efficient and Environmental Buildings.
Examiner: Hans Bagge (Building Physics)Supervisor: Dennis Johansson (HVAC)Keywords: Underfloor heating, Energy, Thermal mass, Energy efficiency, Heating systems
Thesis: EEBDâ15/10
Underfloor heating- a solution or a problem
Table of content
1 Background ............................................................................................... 1
Energy and environmental issues 1 1.1
1.1.1 EU directives 1
1.1.1.1 National targets 1
1.1.2 Energy in Swedish residential buildings 1
Underfloor heating 2 1.2
1.2.1 Possible benefits of underfloor heating 2
1.2.2 Possible disadvantages with underfloor heating 2
1.2.3 Floor materials 3
1.2.4 System control 4
1.2.5 Underfloor heating in combination with heat pumps 4
Objectives 4 1.3
Limitations 4 1.4
2 Method ...................................................................................................... 7
Questionnaire study 7 2.1
Indoor climate measurements 8 2.2
2.2.1 Loggers and outdoor climate 8
2.2.2 Sorting of values 8
2.2.3 Analyses of the measured houses 9
Simulations 9 2.3
Industry knowledge and directives 9 2.4
3 Results and analysis ................................................................................ 11
Questionnaire study 11 3.1
3.1.1 Overall satisfaction 11
3.1.2 Discomforts 12
3.1.2.1 During heating season 13
3.1.2.2 During the whole year 13
3.1.3 Flooring materials 15
3.1.3.1 Cold floors 17
3.1.3.2 Varying temperature with different flooring materials 17
3.1.4 Wanted temperature 19
Underfloor heating- a solution or a problem
Indoor climate measurements 19 3.2
3.2.1 Temperature measurements 20
3.2.1.1 Distribution of logged temperatures 20
3.2.1.2 Influence of the outside temperature 25
3.2.1.3 Comparison between the two measured systems 26
3.2.2 Humidity measurements 27
3.2.2.1 Comparison between the two measured systems 33
3.2.2.2 Influence of the outside relative humidity 34
3.2.3 Analysing the measured residences 35
3.2.3.1 Comparing with the questionnaire answers 35
3.2.3.2 Moisture addition 36
Simulations 38 3.3
3.3.1 Energy simulations 39
3.3.2 Thermal mass 40
4 Discussion ............................................................................................... 43
Industry knowledge 43 4.1
Questionnaire study 43 4.2
Indoor climate measurements 45 4.3
Simulations 46 4.4
5 Conclusions ............................................................................................. 49
6 Future work ............................................................................................. 51
References ....................................................................................................... 54
Appendix A ..................................................................................................... 56
Appendix B ...................................................................................................... 57
1
1 Background
Energy and environmental issues 1.1
According to the Intergovernmental Panel on Climate Change, IPCC, it is clear that humans
have had a grave impact on the climate changes that has taken place since the 1950s. The
atmosphere and the oceans are getting warmer which causes ice and snow to melt, raises the
sea-levels and increases the risk for natural disasters. The anthropogenic emissions of
greenhouse gases are at an all-time high, much because of the persistent use of fossil fuels.
80% of the worldâs energy use still comes from fossil fuels. This might come as a surprise
since the negative impact of using fossil fuel is well known and that the environmental
question often is high on the political agenda. (IPCC,2013)
There are several reasons for this, one being the exponential increase of human population,
another is that although highly developed countries use of fossil fuel decreases the use in
less developed countries increases as they are reaching for quick and cheap changes.
Renewable energy sources, which have a much lower emission of greenhouse gases than
fossil fuels, are becoming more evolved and more common. This is a step in the right
direction, but it is not the only solution. In order to more effectively decrease the
environmental impact the use of energy should be lowered.
1.1.1 EU directives
In March 2007 the European Union leaders set new targets for its members in order to try
reducing the environmental impact and to support the development of renewable energy
sources. The three major objectives are; a 20% reduction in EU greenhouse gas emissions
from 1990 levels, raising the share of EU energy consumption produced from renewable
resources to 20 % and a 20% improvement in the EUâs energy efficiency. Because of these
three key objectives the targets are known as the â20-20-20â targets and are aimed to be
fulfilled in 2020.
1.1.1.1 National targets
The Effort Sharing Decision sets national targets for 2020 which is binding for each member
in the European Union. This decision targets the 60% of greenhouse gas emissions that is
not produced by the industrial sector and therefore not covered by the EU Emission Trading
System. The targets which is expressed in percentage-change from 2005s levels is decided
by the wealth of each country, this means that a wealthy country have to lower its emissions
more than a less wealthy. A less wealthy country is even allowed to increase their
percentage in order to leave space for a growing economy, the main goal is that in 2020 the
greenhouse gas emissions (covered by the Effort Sharing Decision) from all members of the
European Union should be lowered by 10%.
1.1.2 Energy in Swedish residential buildings
As set by the Effort Sharing Decision Sweden needs to lower its greenhouse emissions
outside the industrial sector with 17% compared to 2005s levels. Greenhouse gases from
residential buildings fall under this category and will be addressed by improving the energy
performance of buildings. (Council of European Union, 2015)
Underfloor heating- a solution or a problem
2
In 2013 the energy consumed within residential buildings in Sweden was 63 427 GWh and
approximately 87% (55181 GWh) of this energy was used to heat the buildings. A good way
to reduce the consumption of energy and thereby lower the impact on the environment could
be to use more efficient heating methods. (Statistikcentralen, 2014)
Underfloor heating 1.2
Underfloor heating is often promoted to be an energy efficient heating method and is
becoming more and more common in Swedish single family houses. 61% of all single
family houses built in Sweden during 1996-2005 was equipped with underfloor heating,
which is a large increase compared to 1986-1995 where only 10% of new buildings where
equipped. (Betsi, 2009)
An underfloor heating system functions similar to the traditional radiator heating system,
but instead of having hot water running through and heating small surfaces, such as
radiators that are placed inside the room, the hot water runs through pipes that are casted in
the foundation under the floor or placed underneath the flooring material and therefore heats
up the larger floor area. According to the Swedish authorities the floor surface should not
exceed 27°C. (T2, 2002)
1.2.1 Possible benefits of underfloor heating
Underfloor heating should take away the factor of cold floors which is a desirable advantage
for many. It is also hidden underneath the flooring and does not take away space or affect
the appearance of the living area.
The human head thrives in a temperature of about 18-20°C but the feet wants a temperature
about 5°C higher than that. If a room is heated from the floor the general temperature in the
room should thereby be able to be lower, because the human feet is the primary sensory
organs for temperature i.e. if the feet are warm we feel warm. This should, according to
experts, allow for a room temperature that is 2-3°C lower and an energy saving of about
15% than if a conventional radiator system were used. (Boverket, 2015)
Since radiators are relatively small in area the water needs to be relatively hot in order to
heat an entire room, the radiated heat will also mostly be located around the radiator. This
should not be the case for underfloor heating. Since the entire floor is heated there is a lot of
contact between the heated floor and the air, which should allow for lower water
temperatures in the system and more dispersed heat in the entire room. (Boverket, 2015)
Utilizing the thermal storage in a building is often a good way to lower the amount of
energy needed to keep a building heated. Since the entire floor is heated when underfloor
heating systems are used there is a lot of mass where the thermal energy can be stored. This
stored energy should help to keep a uniform indoor temperature throughout the day and
lower the energy need.
1.2.2 Possible disadvantages with underfloor heating
Floor heating systems radiates the same amount of heat up to the building as it does down to
the foundation, it is therefore important to have a lot of insulation in the foundation to
prevent the energy from being wasted in to the ground. According to Swedish authorities
and experts it is recommended to have at least 250 millimetres of insulation below the floor
Underfloor heating- a solution or a problem
3
heating system. This will lead to a higher initial cost of the system and can be hard to
implement when renovating or rebuilding. (Boverket, 2015)
It is also debatable that since such a large surface is heated by the system it is not to
recommend if the demand of energy is low. It will always take a certain amount of energy to
heat this large surface, which leads to that the minimum amount of energy that can be
provided by an underfloor heating system is higher than systems that uses smaller surfaces.
If the system is used in a well-insulated building with an energy demand that is lower than
the minimum energy that can be provided, the system may turn on and off and thereby
provide uneven temperatures and waste energy. This can make the underfloor heating
system difficult in new buildings where it is common to have a lot of insulation in order to
reach the energy goals.
Since it is common to have the floor heating casted inside the concrete, which can store a lot
of heat, there will be a time delay before any changes of heat supply will influence the
temperature of the room. This means that if the temperature outdoor rapidly changes it will
take time before the heating system adapts, which can lead to both overheated and cold
indoor climate. If the building has large windows and a slowly adapted heating system, solar
energy in combination with the stored energy in the concrete can rapidly increase the indoor
temperature and lead to uneven temperatures and overheating.
It is common to place radiators underneath windows to avoid downdraughts from the cold
window surfaces, which is not possible with an under floor heating system. To avoid this
complication the Swedish authorities and experts recommend that window constructions
with a U-value below 1.0 W/(mÂČK) are installed. These window constructions are expensive
and this will raise the price of installing underfloor heating both in new buildings and
renovations. (Boverket, 2015)
It can also be argued that there is an increased risk of water damage with a floor heating
system compared with other heating systems. If there is a leak in any of the water pipes in
the floor it would be hard to detect in time and the water damage it causes could be very
extensive. A discussion with Vattenskadecentrum (Water damage center) revealed no
known, apparent increase of such risks.
1.2.3 Floor materials
The type of flooring material chosen when using an underfloor heating system can have a
high impact on how the system works. If a heavy material, such as stone that stores a lot of
heat, is chosen it should create a system that takes a relatively long time to influence the
temperature in the room. When the outdoor temperature quickly drops this can help to keep
an even indoor temperature, but when the outdoor temperature quickly raises or the sun
starts to shine the combined energies could create overheating since the heating system is
slow to adapt. If a lighter material, such as parquet floor, that does not store so much heat, is
chosen the heating system should be quicker to adapt to changing conditions. If the outdoor
temperature then quickly raises or the sun starts shining the flooring material does not have
a lot of energy stored and will faster adapt. The same goes for if the temperature outside
rapidly drops.
Underfloor heating- a solution or a problem
4
1.2.4 System control
There are different ways on how the underfloor heating can be controlled. The standard
being a thermostat either in the floor or in the room, this could create problems since heat
from other sources is not taken under consideration. There is a more energy efficient way
where the thermostat measures the temperature both in the floor and in the room at the same
time and thereby utilizes heat from other sources such as the sun or people. (T2, 2002)
1.2.5 Underfloor heating in combination with heat pumps
A heat pump can be used in combinations with an underfloor heating system. The efficiency
of the heat pump is called the Coefficient of Performance (COP) and is the ratio between the
energy usage of the compressor and amount of useful heat extracted from the condenser.
The COP for a heat pump is affected by several factors, one being the temperature
difference between the heat distribution and the heat source. The lower this temperature lift
is the higher the COP of the heat pump will be. See Figure 1.1 for example. (Berntsson,
2000)
Figure 1.1 COP difference with different temperature lifts with different types of heat pumps
Since an underfloor heating system operates with a lower temperature than for example a
radiator heating system the temperature lift will be lower when using this system, giving the
heat pump a higher COP. If a heat pump is used in combination with a heating system it is
therefore more beneficial to use an underfloor heating system.
Objectives 1.3
Underfloor heating has both advantages and disadvantages in different perspectives
regarding energy use, indoor climate and economy. Particularly the option to utilize the
thermal mass is influence with an underfloor heating system. This thesis will investigate the
existing knowledge on issue of underfloor heating and how residents with underfloor
heating perceive their indoor climate by a questionnaire. It will also include indoor climate
measurements and energy simulations to try to resolve important factors influencing the
energy use and indoor climate by use of underfloor heating.
Limitations 1.4
This thesis has limited its research to single family houses and thereby taking away the
factor of heating from others dwellings. Electric floor heating is not investigated in this
study, since it is considered having to high primary energy use to be worthwhile.
The underfloor heating system is only looked at as a heating system in this thesis and not as
a cooling system where cold water is run through instead of hot water.
TYPE OF HEAT PUMP 20°C 25°C 30°C 35°C 40°C 45°C 50°C 55°C 60°C
Earth source (G & W) 9.26 7.15 5.8 4.8 4.15 3.6 3.2 2.9 2.6
High efficiency ASHP 7.5 5.9 4.75 3.9 3.4 3 2.25 2 1.9
Standard ASHP 4.5 3.5 2.5 1.9 1.8 1.7 1.6 1.5 1.4
Variation of COP for different heat pumps with temperature liftLIFT (°C)
Underfloor heating- a solution or a problem
5
Measurements and simulations made in this study are limited to two heating systems, water
radiator heating systems and water underfloor heating systems.
Results from simulations are based on the geographical location Helsingborg in Sweden and
any conclusions based on these results may not be representative for different locations.
Underfloor heating- a solution or a problem
6
Underfloor heating- a solution or a problem
7
2 Method
In this chapter the different methods used in order to fulfil the objectives of this thesis is
presented.
Questionnaire study 2.1
In order to determine how pleased residents are and how they perceive their indoor climate
with underfloor heating it was decided that a questionnaire study needed to be conducted. In
order to get sensible results the single family houses targeted in the study needs to fulfil
different requirements. The houses could not be too old since underfloor heating is rarer in
older buildings and building standards have changed. Row houses and multiple family
houses should be avoided because of the heat transfer between apartments or houses. If
possible the targeted houses should have the same outdoor climate and thereby be affected
by climate changes in the same way. It would also be preferred if the houses had different
types of heating system in order to compare the results.
It was, because of previous mentioned reasons, decided that to hand out paper
questionnaires directly to the houses would be the most efficient way to carry out the study.
By doing it this way, houses that did not meet the requirements could be skipped and only
information valuable to the study would be collected. A relatively new built residential area
with a lot of single family houses would fit well, both because of logistic reasons and that
the houses would share the same outdoor climate. The questionnaires were delivered with a
pre-stamped envelope and a covering letter (see Appendix A) that explains how and why the
study is conducted.
The questionnaire used is a composition between two surveys made by Boverket (small
houses and adult) and a series of made up questions that were relevant to this thesis. In order
to not reveal that the study is about underfloor heating or heating systems, which could
affect the residentsâ answers, the headline of the questionnaire was âA few questions about
your indoor climateâ and also contains some questions that are not relevant to the study. In
the survey (which can be seen in appendix B in Swedish) the residents answers questions on
a scale from either 1-5 or 1-3 on how pleased they are with aspects of their indoor climate
regarding different phenomenon, changing outdoor climate etc. The questionnaire also
contains questions about which types of flooring material the house has and which types of
heating systems that exists. The respondents will be able to remain anonymous or will be
able to fill in their name and phone number and thereby accepting further questioning if
needed.
The results from the questionnaire study will be analysed and answers from houses with
different heating systems will be compared, the level of satisfaction with underfloor heating
in different aspects will try to be determined and the most common floor materials will
affect the upcoming simulations in this thesis.
Maria Park, a residential area located a few kilometres north of Helsingborg in Sweden, was
chosen to be the target area of this study. It was chosen because it is a large residential area
(which means a lot of potential respondents), it is relatively new built and has a lot of single
family houses that does not have the same type of heating systems.
Underfloor heating- a solution or a problem
8
A total of 400 surveys were handed out directly to the mailbox of houses in Maria Park.
They were only handed out to buildings that looked to fit the requirements, houses that did
not were skipped.
Indoor climate measurements 2.2
In order to get a more detailed view of how the indoor climate changes with different
factors, it was decided that temperature and humidity measurements needs to be made on
single family houses with water underfloor heating systems and the more traditional water
radiator heating systems. Respondents from the questionnaire study with these types of
heating systems will be selected and asked if they allow for measuring in their homes. The
selected responders should meet the requirements mentioned in chapter 2.1. They should
especially share the same outdoor climate in order to be able to be compared with each
other.
The purpose of doing these measurements will be to try to see how and how fast the two
different systems adapts to changes in the outdoor climate, if the indoor temperature varies
more with one system compared to the other and if the average temperature with an
underfloor heating system is lower than with a radiator heating system.
In order to collect data when the outdoor climate creates interesting conditions and to be
sure that the heating systems would be turned on, the measuring period for all measured
houses was set to be between the 20th March and the 10
th of April (during the heating
season).
2.2.1 Loggers and outdoor climate
The loggers used in the measuring was OnsetÂź HOBOÂź temp/RH loggers which has a
margin of error of ±0.21°C for temperature and a 2.5% accuracy for relative humidity. Since
±0.21°C does not make a significant difference in these measurements it was discussed and
decided that this should be ignored. The relative humidity was on the other hand corrected
since 2.5% makes a significant difference in the range of the data that was collected. The
logger registered values every fifth minute for both temperature and relative humidity.
(Onset, 2015)
The residents were instructed not to place the logger in direct sun light, on the floor or in a
box or cabinet. It was recommended to place the logger in the hall or living room where the
humidity from the kitchen or the bathroom affected as little as possible.
Data for the outdoor climate was taken from SMHIâs measurements of Helsingborg for the
time of interest. SMHIâs temperature and relative humidity measurements were given,
unlike the loggers, for every hour. (SMHI, 2015)
2.2.2 Sorting of values
Microsoft Excel was used to sort and analyse the measurements, all values was scanned in
order to detect unrealistic values that could have been caused by residents moving the
loggers. No such values were detected.
Since the measurements from SMHI was given every hour and the measurements from the
loggers every fifth minute the values did not enter the same rows in excel. This was
problematic because diagrams that include both measurements, in order to analyse the
Underfloor heating- a solution or a problem
9
results, were required. A macro was written in excel to insert eleven empty rows between
every value given from SMHI and thereby matching the loggers values. The macro can be
seen in Figure 2.1.
Figure 2.1 Macro used to insert eleven empty rows between every value in Excel
2.2.3 Analyses of the measured houses
In order to see how well the residents perceive their indoor climate, the answers of the
questionnaire study (for the measured houses) were compared with the measured data. To
give a clearer view on how the buildings are used, moisture supply were calculated for each
measured residences.
Simulations 2.3
Many of the possible advantages and disadvantages of having underfloor heating systems
comes from the fact that the system heats up a large area and then uses this stored energy to
create an even indoor climate throughout the day. It is also alleged that an underfloor
heating system allows for a lower room temperature and because of that needs less energy.
To try to determine if the possible advantages and disadvantages with an underfloor heating
system, which is more explained in chapter 1.2.1 and 1.2.2, is correct a series of simulations
will be made using Design Builder, which is an interface program for EnergyPlus.
The simulated building in this study will be a 16 m times 12 m one story single family
house. Two different heating systems will be used, water underfloor system and water
radiator system. Different flooring materials will be used based on the results from the
questionnaire study and different U-values on building components will be used in order to
try to see how this affects the energy consumption and balance of the systems.
Industry knowledge and directives 2.4
To be able to determine the possible advantages and disadvantages of using an underfloor
heating system and try to investigate the ones that cannot be investigated through
simulations, a literature study and interviews with expert and authorities will be conducted.
This study will also aim to find out the level of knowledge and what types of guidelines that
exist in the building industry.
The possible advantages and disadvantages found through this study are described in
chapter 1.1.2-1.2.2 and the conclusions of this study will be discussed in chapter 4.
Underfloor heating- a solution or a problem
10
Underfloor heating- a solution or a problem
11
3 Results and analysis
In this chapter the results from the different studies are presented and analysed. Some
discoveries and interesting results are pointed out and shortly commented but will be more
discussed in chapter 4.
Questionnaire study 3.1
Off the 400 residents asked 141 responded, which is an answering rate of approximately
35%, most of them responding anonymously. 120 residences used underfloor heating and 21
used other heating systems.
The results of these 141 answered questionnaires were compared and analysed using
Microsoft Excel. In order to compare underfloor heating systems (shortened UFH) with
other systems, answered questionnaires with underfloor heating was sorted out, these results
was then compared with results from answered questionnaires with different heating system
(which is referred to in this thesis as âotherâ). In order to analyse the results, an average of
the answers is calculated and the percentile for 97.5% and 2.5% are used to see the spread of
the answers. The percentile is a measure that indicates the value where the given percentage
of observations in a group of observations is below, for example if the 97.5 percentile is 20,
97.5% of all values are below 20.
3.1.1 Overall satisfaction
The respondents have answered questions on how satisfied or dissatisfied they are with their
residence on a scale from 1-5, 1 being satisfied and 5 being dissatisfied. Underfloor heating
systems are compared with other heating systems in order to try to see if this system is more
satisfying.
Underfloor heating- a solution or a problem
12
Figure 3.1 Results from the overall satisfaction questions in the survey. The higher the number on the x-
axis is the more dissatisfied the responders are.
In all questions seen in Figure 3.1 residences with underfloor heating is on average slightly
more satisfying than residences that use other heating systems. The spread in the answers
are however greater with underfloor heating system, this shows that responders that are
dissatisfied with energy use and thermal comfort of their residence are more dissatisfied if
they have an underfloor heating system. This is particularly evident regarding energy use.
High energy use on an underfloor heating system could indicate that the heat is wasted,
either by lack of insulation or by factors that forces the system to turn on and off in order to
keep the wanted indoor temperature. It could also mean that the residences with underfloor
heating systems do not have a lower indoor temperature than residences with other heating
methods.
3.1.2 Discomforts
The respondents answered questions on how often they experience different discomforts
such as draught or unsatisfying indoor temperatures. Answers were given on a scale from 1-
3, 3 being never, 2 being sometimes and 1 being often.
The goal of these questions was to try to see if different discomforts are more common or
less common when using an underfloor heating system and try to see if it is harder to control
these types of systems.
1.281.45
1.84 1.901.78 1.80
0
1
2
3
4
5
How satisfiedare you with
your residenceas a whole?
(UFH)
How satisfiedare you with
your residenceas a whole?
(Other)
How satisfiedare you with
your residenceregarding
energy use?(UFH)
How satisfiedare you with
your residenceregarding
energy use?(Other)
How satisfiedare you withthe thermalcomfort in
yourresidence?
(UFH)
How satisfiedare you withthe thermalcomfort in
yourresidence?
(Other)
Percentile 97.5
Average
Percentile 2.5
Underfloor heating- a solution or a problem
13
3.1.2.1 During heating season
Since the heating systems is mostly used during the heating season and since interesting
conditions are in place during this time some questions are asked only for this time frame.
The interesting conditions being that the solar energy is affecting the indoor climate even
though it is still cold outside. On the x-axis 3 means never, 2 means sometimes and 1 means
often.
Figure 3.2 Results of discomfort factors during the heating season
As seen in Figure 3.2 underfloor heating systems do not differ much from other systems
regarding discomfort during heating season. Interesting is that when the respondent have
problems with varying room temperatures they have more problem with underfloor heating
systems than other systems even though the average is better. Draught does not appear to be
more problematic in houses with underfloor heating and it is more common with high
temperatures when using other systems.
3.1.2.2 During the whole year
The respondents were then asked if and how frequent discomforting temperatures occur in
their residence during the summer and the winter.
2.73 2.80 2.66 2.45 2.43 2.35
0
1
2
3
4
Have you during the last 3 month (dec-feb) been troubled by....
Percentile 97.5
Average
Percentile 2.5
Underfloor heating- a solution or a problem
14
Figure 3.3 Survey results of discomforting indoor temperatures during summer and winter
The respondents view on discomforting temperatures during summer or winter in their
residence is almost the same whether they have an underfloor heating system or not (as seen
in Figure 3.3). The only difference is that underfloor heating systems have a slightly better
average when it comes to uncomfortable cold temperatures during winter time. Highest
discomfort is with high temperatures during summer time.
The responders were asked if and how often different types of draught occurred in their
residence and if and how often they experience cold floors. This is interesting since
underfloor heating systems does not prevent downdraught in the same way as for example
radiator heating systems.
Figure 3.4 Survey results on frequency of different discomforting factors
2.69 2.60 2.80 2.80 2.98 3.00
2.25 2.25
0
1
2
3
4
Are you in your residence troubled by...
Percentile97.5Average
Percentile 2.5
2.72 2.70 2.80 2.90 2.72 2.75
0
1
2
3
4
Are you in your residence troubled by...
Percentile 97.5
Average
Percentile 2.5
Underfloor heating- a solution or a problem
15
As seen in Figure 3.4 downdraught from windows does not occur especially often in
residence with underfloor heating systems, which could be a possible disadvantage of using
this system, although it is more common than when using other systems. Another interesting
result is that cold floors is nearly as common in underfloor heating systems as it is in other
systems even though the heat radiates from the floor.
To try to see if underfloor heating systems are harder to control than other systems and if the
temperature varies during changes in the outdoor temperature, the respondents answered
questions on how they perceive these issues.
Figure 3.5 Results on how respondents perceive varying room temperatures and difficulty to influence the
this temperature
As seen in Figure 3.5 it is more common to have varying room temperature during
temperature changes outside when using an underfloor heating system. This indicates that
this system is slow to adapt to changing conditions. When the respondents have difficulty to
influence the room temperature they have a higher level of difficulty if they use an
underfloor heating system. Despite that it is more common to have a problem with this if
another system is used.
3.1.3 Flooring materials
To see which flooring material that is the most common when using underfloor heating
systems, the respondents answered questions on which types of flooring materials they have,
both on the ground floor and upstairs floors. It is also of interest to see if the designers of the
buildings prefer to use a flooring material that stores much heat or a material that stores
lower amounts of heat. These results are presented in percent of how many of the residences
that have a specific type of flooring material above an underfloor heating system.
2.29 2.55 2.50 2.25
0
1
2
3
4
varying roomtemperatures
duringtemperature
changes outside(UFH)
varying roomtemperatures
duringtemperature
changes outside(other)
difficulty toinfluence room
temperature(UFH)
difficulty toinfluence room
temperature(other)
Are you in your residence troubled by...
Percentile 97.5
Average
Percentile 2.5
Underfloor heating- a solution or a problem
16
Figure 3.6 Results in percentage on how common certain flooring materials above underfloor heating is on
the ground floor
Figure 3.7 Results in percentage on how common certain flooring materials above underfloor heating is on
upstairs floors
From the results that is presented in Figure 3.6 and Figure 3.7 it is clear that wooden
flooring and tiled flooring, often in combination (which is the reason the percentâs adds up
to more than 100), is the most common flooring material when using underfloor heating
systems. These two flooring materials will therefore be used and analysed in the upcoming
simulations. It is approximately equally common with tiled as it is with wooden flooring and
therefore the results do not answer if a heavy flooring material is more preferred than a
lighter. The results also show that 70% of all respondents with underfloor heating systems
do not have underfloor heating systems on the upstairs floors. This can be explained by that
it takes a lot of labour to put in all the piping to have an underfloor heating system on
upstairs floors, which in turn can cost more than it gives.
2.5%
84.2% 85.8%
9.2%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
PVC-/vinyl floor Wood/woodparquet
Tiled Stone
0.8%
14.2% 20.8%
1.7%
70.0%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Carpeted Wood/woodparquet
Tiled Stone No underfloorheating upstairs
Underfloor heating- a solution or a problem
17
3.1.3.1 Cold floors
According to the survey residents with underfloor heating systems experience cold floors
nearly as much as residents without this system, which is peculiar since the heat is supplied
from the floor. In order to try to find a reason for this the surveys where cold floors were a
discomfort was sorted out to see which flooring material these houses have.
Figure 3.8 Flooring materials when having discomfort with cold floors and using an underfloor heating
system
As seen in Figure 3.8 it is most common to have a combination of tiled flooring and wooden
flooring. 82% of the houses in this study have that combination above their underfloor
heating system. It is therefore hard to be sure if one material causes cold floors more than
the other. It is only residents with these three flooring materials that have problems with
cold floors.
3.1.3.2 Varying temperature with different flooring materials
As explained in chapter 1.2.3 the flooring material can have an impact on how much the
indoor temperature varies with an underfloor heating system. In order to try to see if the
flooring material influences the varying indoor temperature, the respondents with this issue
was sorted out and the flooring materials of this residences was compared. This is done to
see if it is more or less common with varying indoor temperature with a lighter of heavier
flooring material.
90.9% 87.9%
3.0%
Wood/wood parquet
Tiled
Stone
Underfloor heating- a solution or a problem
18
Figure 3.9 Flooring material when having problems with varying indoor temperature caused by changing
outdoor temperature
As seen in Figure 3.9 it is slightly more common to have a heavy flooring material when
having problems with varying indoor temperature, the difference is although very small. In
order to investigate this further, only residence that often has problems with varying
temperature (answer 3) is sorted out and their flooring materials are compared.
Figure 3.10 Flooring material when often having problems with varying indoor temperature caused by
changing outdoor temperature
In Figure 3.10 the difference is clearer, it is more common with heavy flooring materials
when often having problem with varying indoor temperature caused by changing
temperature outdoors.
82.9%
2.7%
85.6%
9.9%
Wood/wood parquet
PVC-/vinyl floor
Tiled
Stone
75.0%
2.3%
84.1%
13.6%
Wood/wood parquet
PVC-/vinyl floor
Tiled
Stone
Underfloor heating- a solution or a problem
19
3.1.4 Wanted temperature
In the survey the respondents answered on which temperature they would like to have in
their residence and which temperature they experience, both for winter and summer. The
average difference between these temperatures would give a result on how close the heating
system is on giving the wanted temperatures, at least how close the respondents perceive it
to be.
Figure 3.11 Results on the difference between wanted and perceived indoor temperature in winter and
summer
As seen in Figure 3.11 the difference in wanted and perceived indoor temperature is very
low during winter time. In summer the difference is, in both underfloor heating and other
systems, much larger but more when using underfloor heating. Some of the respondents
using this system could even perceive temperatures more than 9°C warmer than what they
would like to have.
Indoor climate measurements 3.2
In the questionnaire study the respondents could leave their name and telephone number and
accept to be contacted if needed. Some respondents did that and a few of them was
contacted and asked if they would allow temperature and humidity measuring in their
residence. Three residences with water radiator systems and four residences with water
underfloor heating systems allowed measuring.
0.07
-1.94
0.15
-1.75
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
Winter (UFH) Summer (UFH) Winter (other) Summer (other)
Temperature difference/°C
Percentile97.5
Average
Percentile2.5
Underfloor heating- a solution or a problem
20
3.2.1 Temperature measurements
One of the possible advantages of underfloor heating is that it should allow a lower indoor
temperature than for example radiator heating systems. In order to see if this is correct, in
the measurements made for this study, an average of all logged temperatures in each
residence was calculated and compared.
Figure 3.12 Results of the average temperatures of the measured residences
As seen in Figure 3.12 only âUnderfloor heating 2â has a significantly lower average
temperature than the residences using radiators. In the other residences the average
temperature is fairly even. The percentiles give an indication that the spread of logged
temperatures is larger in the residences that uses underfloor heating systems.
3.2.1.1 Distribution of logged temperatures
To take a closer look on the spread and to some extent see how much the indoor temperature
varies, the logged temperatures were sorted from smallest to largest and then compared.
Underfloor heating- a solution or a problem
21
Figure 3.13 Variation in temperature for the measured residences
In Figure 3.13 it can be seen that the radiator systems (the line of Radiator 1 is underneath
the line of Radiator 2) has a spread that is more even than the underfloor heating systems.
The temperature in all residences seems to more or less follow the curve of the outdoor
temperature. The underfloor heating systems have more thermal spikes, which could
indicate that these systems are slower to adapt to raising outdoor temperatures or solar
gains.
To try to see how fast the heating system in each residence adapted to changing outdoor
temperatures, the measured indoor temperature was compared with the outdoor temperature.
Looking for heat peaks indoors and if they occur shortly after raising temperatures outside,
also to try to see how high these peaks gets. In figure 3.14-3.20 this comparison is presented
for each residence.
Figure 3.14 Inside temperature for Radiator 1 compared with the outside temperature
-10
-5
0
5
10
15
15
16
17
18
19
20
21
22
23
24
25
26
0 1000 2000 3000 4000 5000 6000
Temperature/°C Temperature/°C
Radiator 1
Radiator 2
Radiator 3
Underfloor heating 1
Underfloor heating 2
Underfloor heating 3
Underfloor heating 4
Outdoors (secondaxis)
-10
-5
0
5
10
15
20
22.5
23
23.5
24
24.5
25
25.5
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
InsideTemp
OutsideTemp
Underfloor heating- a solution or a problem
22
Figure 3.15 Inside temperature for Radiator 2 compared with the outside temperature
Figure 3.16 Inside temperature for Radiator 3 compared with the outside temperature
Figure 3.17 Inside temperature for Underfloor heating 1 compared with the outside temperature
-10
-5
0
5
10
15
20
22.5
23
23.5
24
24.5
25
25.5
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
Insidetemp
OutsideTemp
-10
-5
0
5
10
15
20
19
19.5
20
20.5
21
21.5
22
22.5
23
23.5
24
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
InsideTemp
OutsideTemp
-10
-5
0
5
10
15
20
21
21.5
22
22.5
23
23.5
24
24.5
25
25.5
26
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
InsideTemp
Outsidetemp
Underfloor heating- a solution or a problem
23
Figure 3.18 Inside temperature for Underfloor heating 2 compared with the outside temperature
Figure 3.19 Inside temperature for Underfloor heating 3 compared with the outside temperature
Figure 3.20 Inside temperature for Underfloor heating 4 compared with the outside temperature
-10
-5
0
5
10
15
20
18
19
20
21
22
23
24
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
InsideTemp
OutsideTemp
-10
-5
0
5
10
15
20
21
21.5
22
22.5
23
23.5
24
24.5
25
25.5
26
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
InsideTemp
OutsideTemp
-10
-5
0
5
10
15
20
19
20
21
22
23
24
25
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Temperature/°C Temperature/°C
InsideTemp
OutsideTemp
Underfloor heating- a solution or a problem
24
It is no surprise that the temperature raises shortly after raising temperatures outside, the
interesting, with the comparisons in Figure 3.14-Figure 3.20, is to see how fast the system
adjusts its heating after these heat peaks outside. After examining these diagrams and the
data behind them it seems that the underfloor heating systems is slower to adapt and
therefore causes higher temperature peaks than radiator systems. To more see how the
temperature differs inside the measured residences the difference between the maximum and
the minimum temperature in each residence was calculated.
Table 3.1 The temperature difference between the maximum and the minimum temperature for every
measured day in the measured residences
Date UFH1/°C UFH2/°C UFH3/°C UFH4/°C Rad1/°C Rad2/°C Rad3/°C
20/03/2015 1.34 0.81 0.96 2.20 0.51 0.46 0.77
21/03/2015 0.86 0.62 0.69 0.76 0.82 1.03 1.01
22/03/2015 2.02 1.43 1.05 2.10 0.87 0.91 1.03
23/03/2015 1.82 1.00 1.51 2.27 0.79 0.38 1.08
24/03/2015 0.77 0.62 0.65 3.31 1.04 0.26 0.96
25/03/2015 0.41 0.40 0.45 3.70 0.91 0.29 0.57
26/03/2015 0.60 0.79 0.41 1.72 1.01 0.22 0.57
27/03/2015 1.37 0.93 0.93 1.89 0.96 0.58 0.88
28/03/2015 1.70 0.74 1.17 2.54 0.98 0.34 0.93
29/03/2015 1.41 0.74 0.62 1.75 1.35 0.22 1.17
30/03/2015 0.96 0.90 1.32 2.89 1.28 0.67 3.39
31/03/2015 0.81 1.12 0.72 0.65 1.11 0.24 1.24
01/04/2015 1.75 0.79 1.58 2.13 1.28 0.41 1.27
02/04/2015 2.86 1.55 1.65 2.09 0.94 0.50 1.27
03/04/2015 2.52 4.63 1.58 2.62 1.15 0.74 1.15
04/04/2015 2.47 2.19 1.73 2.81 1.08 0.77 1.41
05/04/2015 2.67 1.43 3.37 2.43 0.70 1.04 1.55
06/04/2015 3.59 2.05 1.42 2.98 2.07 2.00 2.01
07/04/2015 1.39 1.00 0.84 1.58 1.71 0.24 1.08
08/04/2015 1.71 2.02 1.82 3.05 1.49 0.67 1.15
09/04/2015 1.66 1.55 2.35 3.48 1.28 0.53 1.44
Average: 1.65 1.30 1.28 2.33 1.11 0.60 1.23
Underfloor heating- a solution or a problem
25
As seen in Table 3.1 it is more common to a have larger temperature difference between the
daily maximum and minimum indoor temperatures when using an underfloor heating
system. When examining Figure 3.18 it looks like Underfloor heating 2 should have a less
varying indoor temperature than the rest of the residences but it has a peak on the third of
April that affects its average in Table 3.1. If this date was to be taken away the average daily
temperature difference would be 1.13°C, which is as good as for a residences using radiator
heating.
3.2.1.2 Influence of the outside temperature
In order to closer investigate how much the outside temperature influences the inside
temperature, diagrams with the indoor temperature as a function of the outside temperature
were made. With the help of Excel a trend line and an equation that shows the connection
between the two variables were added.
Figure 3.21 The inside temperature as a function of the outside temperature in Underfloor heating 1
As seen in Figure 3.21 there is, unsurprisingly, a connection between the outdoor and indoor
temperature. The interesting being the factor in front of x (for future references called k) in
the equation, the closer this factor k is to one the larger the connection is between the
outside and inside temperature. The coefficient of determination (RÂČ) describes how well
one variable describes the other, in this case how well the outdoor temperature describes the
indoor. If RÂČ is between minus one and zero the connection is negative, if it is zero there is
no connection and if it is between zero and one the connection is positive. This analysis was
made for all measured residences and the resulting coefficients are presented in the table
below.
y = 0.1054x + 22.526 RÂČ = 0.1947
21.5
22
22.5
23
23.5
24
24.5
25
25.5
26
-10 -5 0 5 10 15 20
Temperature/°C
Temperature/°C
Underfloor heating- a solution or a problem
26
Table 3.2 The connection variables for the indoor and outdoor temperatures in the measured residences
k RÂČ Average
k
Average
RÂČ
Underfloor heating 1 0.1054 0.1947
0.0842
0.1128
Underfloor heating 2 0.0320 0.0317
Underfloor heating 3 0.0527 0.0526
Underfloor heating 4 0.1467 0.1720
Radiator 1 0.0286 0.0399
0.0300
0.0833 Radiator 2 0.0145 0.0195
Radiator3 0.0467 0.1904
It seems like the outdoor temperature has a slightly larger influence on the indoor
temperature when using underfloor heating systems. The average coefficients k and RÂČ are
larger for the residences with underfloor heating systems.
3.2.1.3 Comparison between the two measured systems
In order to see how the two different systems compare with each other, interesting values
such as average temperature, maximum and minimum temperature, for the measured
temperatures of all residences with underfloor heating was compared with the values of all
residences with radiator heating systems.
Table 3.3 Temperature comparisons between the two systems
Underfloor heating Radiators
Average temperature/°C 21.81 23.35
Standard deviation/°C 1.556 0.459
Maximum temperature/°C 25.525 25.113
Percentile 95/°C 24.026 24.120
Percentile 75/°C 22.848 23.597
Percentile 50/°C 22.178 23.328
Percentile 25/°C 20.674 23.117
Percentile 5/°C 19.08 22.853
Minimum temperature/°C 18.604 21.036
The standard deviation is a distribution measurement on how the values are distributed
around the average value. As seen in Table 3.3 the average temperature is lower in the
residences with underfloor heating but the standard deviations is larger, which indicates that
temperatures when using this system varies more.
Underfloor heating- a solution or a problem
27
3.2.2 Humidity measurements
In order to see if there is any differences in humidity levels when using underfloor heating
systems or radiator heating systems the same comparisons made with temperature in chapter
3.2.3 was made for the measured humidity.
Figure 3.22 Results of the average relative humidity in the measured residences
In Figure 3.22 it is showed that there is no significant difference in the average relative
humidity levels when using underfloor or radiator heating systems. The spread of the levels
differs a lot from residence to residence and will therefore be further investigated.
To try to see if there is more spread in relative humidity levels with the different heating
systems, the measured values was sorted from smallest to largest and then compared.
35.44 35.8136.54
31.22
37.79
34.87
38.40
25
30
35
40
45
50
Radiator 1 Radiator 2 Radiator 3 Underfloorheating 1
Underfloorheating 2
Underfloorheating 3
Underfloorheating 4
Relative humidity/%
97.5 percentile
Average
2.5 percentile
Underfloor heating- a solution or a problem
28
Figure 3.23 Variation in relative humidity for the measured residences
Figure 3.23 show that the residences using radiator heating systems have more high values
of relative humidity, the residences with underfloor heating have more even relative
humidity levels.
To try to see how the relative humidity changes with the indoor temperature, these values
were compared and analysed. This should give an indication of when the high level of
relative humidity occurs.
Figure 3.24 Indoor relative humidity for Radiator 1 compared with the indoor temperature
40
50
60
70
80
90
100
20
25
30
35
40
45
50
55
60
0 2000 4000 6000
Relative humidity/%
Relative humidity/%
Radiator 1
Radiator 2
Radiator3
Underfloorheating 1Underfloorheating 2Underfloorheating 3Underfloorheating 4Outside(second axis)
25
30
35
40
45
50
22.5
23
23.5
24
24.5
25
25.5
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
Underfloor heating- a solution or a problem
29
Figure 3.25 Indoor relative humidity for Radiator 2 compared with the indoor temperature
Figure 3.26 Indoor relative humidity for Radiator 3 compared with the indoor temperature
Figure 3.27 Indoor relative humidity for Underfloor heating 1 compared with the indoor temperature
20
30
40
50
22.5
23
23.5
24
24.5
25
25.5
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
20
25
30
35
40
45
50
55
19
19.5
20
20.5
21
21.5
22
22.5
23
23.5
24
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
20
30
40
21
21.5
22
22.5
23
23.5
24
24.5
25
25.5
26
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
Underfloor heating- a solution or a problem
30
Figure 3.28 Indoor relative humidity for Underfloor heating 2 compared with the indoor temperature
Figure 3.29 Indoor relative humidity for Underfloor heating 3 compared with the indoor temperature
Figure 3.30 Indoor relative humidity for Underfloor heating 4 compared with the indoor temperature
30
40
50
18
19
20
21
22
23
24
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
25
30
35
40
45
21
21.5
22
22.5
23
23.5
24
24.5
25
25.5
26
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
20
25
30
35
40
45
50
55
19
20
21
22
23
24
25
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Temperature/°C
Indoortemp
IndoorRH
Underfloor heating- a solution or a problem
31
The relative humidity is the amount of humidity (in g/mÂł) in the air divided by the amount
of humidity the air can carry (in g/mÂł) and the higher temperature of the air, the more
humidity it can carry. This should, if no other factors influences mean that if the indoor
temperature increases the relative humidity should decrease. As seen in Figure 3.24-Figure
3.30 this is the case on some occasions but not all the time, which than means that there is
other factors influencing the indoor relative humidity. Since the indoor temperature affects
the indoor relative humidity it can be seen that residences with a more even temperature has
a more even relative humidity. The peaks and drops in relative humidity often appear with
changes in the temperature.
Another factor that can affect the indoor relative humidity is the outdoor relative humidity,
in order to see how this affects these two relative humidityâs was compared.
Figure 3.31 Relative humidity for Radiator 1 compared with the outdoor relative humidity
Figure 3.32 Relative humidity for Radiator 2 compared with the outdoor relative humidity
40
50
60
70
80
90
100
20
25
30
35
40
45
50
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
40
50
60
70
80
90
100
20
25
30
35
40
45
50
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
Underfloor heating- a solution or a problem
32
Figure 3.33 Relative humidity for Radiator 3 compared with the outdoor relative humidity
Figure 3.34 Relative humidity for Underfloor heating 1 compared with the outdoor relative humidity
Figure 3.35 Relative humidity for Underfloor heating 2 compared with the outdoor relative humidity
40
50
60
70
80
90
100
20
25
30
35
40
45
50
55
60
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
40
50
60
70
80
90
100
20
22
24
26
28
30
32
34
36
38
40
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
40
50
60
70
80
90
100
3032343638404244464850
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
Underfloor heating- a solution or a problem
33
Figure 3.36 Relative humidity for Underfloor heating 3 compared with the outdoor relative humidity
Figure 3.37 Relative humidity for Underfloor heating 4 compared with the outdoor relative humidity
As seen in Figure 3.31-Figure 3.37 the indoor relative humidity curve mostly follows the
curve of the outdoor relative humidity in all residences, with an even difference. In some
cases the relative humidity indoors is high even through the outdoors relative humidity is
relatively low, this could be due to the presence of people, which produce both heat and
moisture.
3.2.2.1 Comparison between the two measured systems
In order to see how the two different systems compare with each other, interesting values
such as average humidity, maximum and minimum humidity, for the measured temperatures
of all residences with underfloor heating was compared with the values of all residences
with radiator heating systems.
40
50
60
70
80
90
100
25
30
35
40
45
50
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
40
50
60
70
80
90
100
20
25
30
35
40
45
50
55
60
19/03/2015 00:00 29/03/2015 00:00 08/04/2015 00:00
Relative humidity/%
Relative humidity/%
IndoorRH
OutdoorRH
Underfloor heating- a solution or a problem
34
Table 3.4 Relative humidity comparisons between the two systems
Underfloor heating Radiators
Average relative humidity/% 35.57 35.93
Standard deviation 4.29 3.59
Maximum relative humidity/% 51.85 55.83
Percentile 95 43.16 41.57
Percentile 75 38.27 37.89
Percentile 50 35.42 36.02
Percentile 25 32.57 33.89
Percentile 5 29.11 29.98
Minimum relative humidity/% 24.54 21.66
As seen in Table 3.4 the relative humidity does not differ much between the two systems.
Which type of heating system that is used probably does not affect the indoor relative
humidity as much as other factors does, for example the outdoor relative humidity.
3.2.2.2 Influence of the outside relative humidity
In order to see how much the outside relative humidity influences the indoor, the same
comparison that was made for temperature in chapter 3.2.1.2 was made for the relative
humidity.
As seen in Table 3.5 there is a clear connection between the outdoor and indoor relative
humidity. It does not seem to matter which heating system that is used, there is probably
other factors in the building that influences this more.
Underfloor heating- a solution or a problem
35
Table 3.5 The connection variables for the indoor and outdoor relative humidity in the measured
residences
k RÂČ Average
k
Average
RÂČ Underfloor heating 1 0.0487 0.0608
0.0932
0.1359 Underfloor heating 2 0.0525 0.043
Underfloor heating 3 0.0736 0.1725
Underfloor heating 4 0.1981 0.2673
Radiator 1 0.0881 0.1005
0.1057
0.1314 Radiator 2 0.0819 0.1091
Radiator3 0.1471 0.1845
3.2.3 Analysing the measured residences
In order to see how well the responders perceive their indoor climate the questionnaire
answers for the measured residences was compared with the measured data. The added
excess moisture was also calculated to try to see how these measured residences were used
during the measuring period.
3.2.3.1 Comparing with the questionnaire answers
Since humans produce both heat and moisture it is interesting to see if and how much the
amount of residents influences the temperature and relative humidity. It is also interesting to
see how accurate the responders are with their perceived temperature and how close the real
temperature is to the wanted.
Table 3.6 Number of residents, the perceived and wanted temperature of the responders compared with
the average temperature and relative humidity in the measured residences
Residents Average
temperature
(°C)
Average relative
humidity (%)
Perceived temperature
during winter (°C)
Wanted
temperature
during
winter (°C) RAD1 2 23.50 35.44 21 21
RAD2 4 23.33 35.81 20 20
RAD3 3 22.03 36.54 22 24
UFH1 2 23.00 31.22 21 21
UFH2 4 19.49 37.79 20 20
UFH3 4 22.41 34.87 20 20
UFH4 5 22.34 38.40 23 23
Underfloor heating- a solution or a problem
36
As seen in Table 3.6 it is not safe to say that more residents will lead to higher average
temperature or relative humidity, even if this would be logical. There are many other factors
that influence these results, such as size of the house and ventilation. The perceived
temperature in the residences is often lower than the measured averages, the exceptions
being UFH2 and UFH4.
Figure 3.38 Questionnaire study answers from the measured residences. The scale on the y-axis describes
how often discomforts occur, 3 being never and 1 being often.
As seen in Figure 3.38 the residents in the measured residences do not experience high
levels of discomforts during the heating season, with the exception of UFH4, which matches
the results from the measurements.
3.2.3.2 Moisture supply
In order to calculate the moisture supply for the measured buildings the following formulas
were used:
(1) đŁ = 4.7815706 + 0.34597292 â đĄ + 0.0099365776 â đĄ2 +
0.00015612096 â đĄ3 + 1.9830825 â 10â6 â đĄ4 + 1.5773396 â 10â8 â đĄ5
đŁ = đ đđĄđąđđđĄđđđ đŁđđđđ đđđđĄđđđĄ/(đ/đ3)
đĄ = đ đđĄđąđđđĄđđđ đĄđđđđđđđĄđąđđ đđ â
(2) đŁđ = (đ/100) â đŁ
đ = đđđđđĄđđŁđ âđąđđđđđĄđŠ/(%)
đŁđ = đŁđđđđ đđđđĄđđđĄ đđđđđđ/(đ/đ3)
0
1
2
3
Hightemperaturesduring heating
season
Varyingtemperaturesduring heating
season
Too cold duringwinter
Too hot duringwinter
Varyingtemperature withchanging outdoor
temperature
Difficulty to affectthe temperature
RAD1
RAD2
RAD3
UFH1
UFH2
UFH3
UFH4
Underfloor heating- a solution or a problem
37
(3) đ = đŁđ â đŁđ
đ = đđđđ đĄđąđđ đ đąđđđđŠ/(đ/đ3)
đŁđ = đŁđđđđ đđđđĄđđđĄ đđąđĄđđđđ/(đ/đ3)
The average moisture supply for the measured residences during the measured time period
is presented in Table 3.7. As seen there is no significant difference between the two systems
moisture supply averages, but the underfloor heating system seems to vary more between
the different houses.
Table 3.7 Average moisture addition for the measured residences during the measured period
Radiator 1 6.12 g/mÂł
Radiator 2 6.12 g/mÂł
Radiator3 5.73 g/mÂł
Underfloor heating 1 5.05 g/mÂł
Underfloor heating 2 4.98 g/mÂł
Underfloor heating 3 5.56 g/mÂł
Underfloor heating 4 6.28 g/mÂł
Radiator average 5.99 g/mÂł
Underfloor heating
average
5.47 g/mÂł
In Figure 3.39 the distribution of the moisture addition are presented. Again it could be said
that the residences using underfloor heating varies more from each other than the residences
using radiator systems. This again is an indication that installing and using underfloor
heating systems correctly seems to be harder than for radiator systems.
Underfloor heating- a solution or a problem
38
Figure 3.39 The distribution of the moisture supply in the measured houses.
Simulations 3.3
To try to see if the energy use in a single family house is lower when using underfloor
heating systems than when using radiator heating systems, how the floor material affects the
energy use and if the thermal storage is more optimised with underfloor heating a series of
simulations was conducted.
Since wood/wood parquet and tiled flooring was the most common materials in the
questionnaire study these materials was used in the simulations. In order to see if there is a
difference between the two systems when having a good insulated building or a bad
insulated building simulations was done for both. The buildings simulated are identical, only
interesting parameters was chanced and these are presented in Table 3.3.8
Table 3.3.8 The different properties of the simulated buildings
Good building Bad building
Wall U-value/ (W/(mÂČK)) 0.1 0.35
Roof U-value/ (W/(mÂČK)) 0.1 0.25
Slab insulation U-value
(W/(mÂČK))
0.149 0.238
Slab insulation thickness/
(mm)
250 141
Windows U-value/ (W/mÂČ) 0.774 1.987
0
2
4
6
8
10
12
20/03/2015 00:00 10/04/2015 00:00
v/(g/mÂł)
Radiator 1
Radiator 2
Radiator3
Underfloor heating 1
Underfloor heating 2
Underfloor heating 3
Underfloor heating 4
Underfloor heating- a solution or a problem
39
Well-insulated buildings are (in the diagrams) shortened with Good, bad insulated buildings
are shortened by Bad. Radiator systems are shortened with RAD and underfloor heating
systems with UFH.
3.3.1 Energy simulations
To see if the energy used to heat a single family house is lower when using underfloor
heating systems than radiator heating systems energy simulations was made with the two
different heating systems and two different flooring materials. A possible advantage of the
underfloor heating system is that it allows for a lower indoor temperature, therefore the
simulations was made for 16°C, 18°C, 20°C, 22°C and 24°C indoor temperature.
Figure 3.40 Simulated annual energy use for a good insulated single family house with different heating
systems and flooring materials
In Figure 3.40 the energy needed to heat a well-insulated single family house to different
temperatures, with different heating methods and different flooring materials over one year
is shown. Underfloor heating with tiles as flooring material is always the most energy
efficient heating system, regardless on the indoor temperature. Radiators with tiled flooring
use less energy than underfloor heating with wood/wood parquet this could be because of
the larger thermal storage capacity of the tiled flooring.
50
70
90
110
130
150
170
190
16°C 18°C 20°C 22°C 24°C
Energy/ (kWh/year/mÂČ)
Good UFH Wood
Good RAD Wood
Good UFH Tiles
Good RAD Tiles
Underfloor heating- a solution or a problem
40
Figure 3.41 Simulated annual energy use for a bad insulated single family house with different heating
systems and flooring materials
In Figure 3.41 the energy needed to heat a badly insulated single family house to different
temperatures, with different heating methods and different flooring materials over one year
is shown. Although the slab has little insulation the underfloor heating system is more
energy efficient than the radiator system, even if the radiator system uses tiled flooring and
the underfloor heating system uses wood/wood parquet.
3.3.2 Thermal mass
In order to see how big of an impact the thermal mass has on the two systems, energy
simulations with different thickness (to represent thermal storage) on the flooring material
was made. This was done to try to see if underfloor heating systems use the thermal mass of
the floor better than radiator systems.
Because the tiled flooring had the lowest energy use this material was used in the
simulations and since the indoor temperature is not relevant for the results of the thermal
mass an indoor temperature of 20°C was used.
50
70
90
110
130
150
170
190
210
230
250
16°C 18°C 20°C 22°C 24°C
Energy/ (kWh/year/mÂČ)
Bad UFH Wood
Bad RAD Wood
Bad UFH Tiles
Bad RAD Tiles
Underfloor heating- a solution or a problem
41
Figure 3.42 Results for energy use with different flooring thicknesses in a well-insulated house
It clearly shows in Figure 3.42 that the yearly energy needed to heat the building gets lower
the more thermal storage that is available in the floor. Since the house with underfloor
heating already has lower energy use it is hard to see if this system utilizes the thermal mass
better than a radiator system. To try to find this out a second comparison was made, where
the energy needed for 20mm flooring material were subtracted from the other thicknesses.
This allows too see how well the different systems utilize added thermal storage, regardless
from the difference in energy use.
Figure 3.43 Differences in energy use with different flooring thicknesses in a well-insulated house
As Figure 3.43 illustrates there is a difference in how well the systems utilizes thermal mass
in the floor, the underfloor heating system takes slightly more advantage of the added mass
than the radiator system.
To see if amount of insulation has an impact on the above presented results the same
comparisons was made for a house that is badly insulated. The interesting point being that
more heat can be lost through the foundation.
24700
24800
24900
25000
25100
25200
25300
25400
25500
20mm 30mm 40mm 50mm 100mm
Energy/(kWh/ year)
Good UFH Tiles
Good RAD Tiles
41
79
113
242
37
71
104
223
0
50
100
150
200
250
300
30mm 40mm 50mm 100mm
Energy/(kWh/ year)
Good UFH Tiles
Good RAD Tiles
Underfloor heating- a solution or a problem
42
Figure 3.44 Results for energy use with different flooring thicknesses in a badly-insulated house
Figure 3.45 Differences in energy use with different flooring thicknesses in a badly-insulated house
Figure 3.44 and Figure 3.45 matches the previous results with that the underfloor heating
system benefits more from added thermal storage in the floor than the radiator system. The
difference between the two systems ability to utilize the thermal mass is however smaller
with a badly-insulated house.
28000
28500
29000
29500
30000
30500
31000
20mm 30mm 40mm 50mm 100mm
Energy/(kWh/ year)
Bad UFH Tiles
Bad RAD Tiles
30
58
88
197
29
57
84
190
0
50
100
150
200
250
30mm 40mm 50mm 100mm
Energy/(kWh/ year)
Bad UFH Tiles
Bad RAD Tiles
Underfloor heating- a solution or a problem
43
4 Discussion
Industry knowledge 4.1
The knowledge on how to use and install an underfloor heating system in the building
industry seems to be quite good but it might not be as well-known as one would like. In any
case it is not hard to find information on the subject. On the other hand this information
often comes from manufacturers of the system and of course makes the underfloor heating
system look like the ideal heating method.
The Swedish Energy Agency, the Swedish Consumer Agency, the National Housing Board
and Formas have in collaboration created a writing called âGrundtips för golvvĂ€rmeâ
(Boverket, 2015) (Basic tips for underfloor heating) and in this writing it is stated what you
should look out for when installing this kind of system. They recommend that 250
millimeters of insulation is used underneath the floor heating and states that the goal of
using underfloor heating is to lower the indoor temperature. To lower the indoor
temperature is according to this writing a prerequisite in order to save energy. Anyone who
wants to install or have underfloor heating systems can easily obtain this information but
one can only hope that they do.
The possible advantages and disadvantages found through the literature study and
interviews with experts on the subject can be seen in chapter 1.2.1 and 1.2.2. One possible
disadvantage is that since such a large area is heated there could be a risk that the system
would overheat. It would thereby not be suited for use in for example passive houses that
are well-insulated. In order for this to be true the underfloor heating systems needs to be
applied underneath the entire floor or at least most of it. It has through this study come to
the writersâ knowledge that passive houses with underfloor heating systems are being build,
where only the floor area close to the walls are fitted with underfloor heating. This allows
for a smaller area to be heated and should prevent the system from overheating. How well
this works is still not known to the author of this thesis but it is regardless an attempt to
address this disadvantage.
Questionnaire study 4.2
Figure 3.1 does not show that, even with the advantages of the hidden underfloor heating
system, residences with this system are more satisfied than residences with other heating
methods. A reason for that can be found in the same figure. If a resident is dissatisfied from
a thermal comfort point of view, it is more so if using underfloor heating. The same goes for
the respondentsâ perception of their residence energy use. This raises the suspicion that if an
underfloor heating system is not installed or used correctly it could be a bad choice. With
that said the respondents using underfloor heating is on average just as satisfied with the
thermal comfort and energy use as respondents with other systems. This can be interpreted
as if an underfloor heating system is installed and used correctly it is at least as satisficing as
other systems regarding thermal comfort and energy use and more satisfying as a whole.
The most important when investigating heating systems is to investigate how it works
during the heating season. Since this is the time of year when the system is in operation, the
solar gains can affect the indoor climate even if it is still cold outside and draught occur
Underfloor heating- a solution or a problem
44
more distinctly during this period. In the questionnaire study the respondents were asked if
they had perceived problems with draught, too high room temperatures or varying room
temperatures during December to February. To have discomforting high temperatures is on
average less common with underfloor heating systems during this period, if too high
temperatures occur it is also more frequent when using other systems. If the respondents
were troubled by varying room temperature it is more frequent with underfloor heating
systems during this period but more common to occur if another system is used.
Draught from windows in buildings using underfloor heating systems is not more common
than when using other systems, this might be surprising since underfloor heating does not
prevent draught. The answer probably lies in that the residences investigated in this study
was relatively new and was equipped with good windows that prevents downdraught. At
least the study proves that if you have an underfloor heating system you do not necessarily
have problems with downdraught.
A risk of using an underfloor heating system was that it is more common to overheat and
create high indoor temperatures than other systems. This does not seem to be the case, at
least not in this study. It is actually perceived more common with overheating during the
heating season with other heating methods. On the other hand the respondents with
underfloor heating perceive to a more varying room temperatures. As mentioned before
underfloor heating can have problems adjusting to changing conditions since there is a lot of
stored heat in the foundation, this is slightly more true if the residence have a heavy flooring
material, as shown in chapter 3.1.3.2. Another reason could be how the system is controlled.
If the system is not controlled with an energy efficient thermostat and only measure the
temperature in the floor it will not be able to adapt quick enough if the indoor temperature
rises. The ability to influence the room temperature is on average perceived to be easier with
underfloor heating but if it is perceived to be hard it is harder with this system. This could
also be explained by not using energy efficient thermostats.
It is more common than not that if the respondent is dissatisfied the respondent is more
dissatisfied if they use underfloor heating systems. This could be because this system
requires more from the rest of the building, it is also a newer system and it seems like the
knowledge in the industry and of the residents is not as well-known as for example more
traditional heating systems. Therefore it could be that this lack of knowledge leads to badly
installed systems that are not in harmony with the rest of the building. Despite that it seems
that it is more common that the underfloor heating system is installed and used correctly and
that the residents with this system is on average more pleased than residents with other
systems.
An interesting result from the questionnaire study was that residents with underfloor heating
experience cold floors just as much as residents with other systems despite the fact that the
heat is supplied from the floor. One way to explain this could be that it is more common
with flooring materials that is perceived to be colder such as stone or tiles when having an
underfloor heating system. As shown in chapter 3.1.3.1 it is hard to prove that this would be
the reason since wooden flooring and tilled flooring is equally common. Another way to
explain this could be with the fact that residents that have underfloor heating expect their
floors to be warmer than residents with other systems. If the system then is turned off,
because the indoor temperature is satisfying, the residents could be more displeased with the
temperature of the floor since they expect it to be warmer.
Underfloor heating- a solution or a problem
45
It is absolutely most common with tiled or wooden flooring when using underfloor heating,
which shows that the fact of using insulating materials like carpeting above the system is
well-known to be a bad idea. Since tiled and wooden flooring is equally common it is
difficult to say which material that is preferred by the designers of the residences. It could
also be hard to control the choice of flooring material since it has a big impact on the
appearance of the room.
The difference between the perceived temperatures and the wanted temperatures is during
winter very small regardless of which system that is being used. Despite that the
respondents with underfloor heating experience less discomforting low temperatures during
this period. Since this probably is the most important aspect of a heating system it is a good
result for the underfloor heating system. In summer the difference is much higher in all
systems, that this should have anything to do with which heating system the respondents
have is unlikely. Hopefully the heating system is turned off during summer.
It seems that underfloor heating systems if used and installed correctly is in most cases more
satisfying than other heating systems.
Indoor climate measurements 4.3
It is claimed by authorities that lowering the indoor temperature is required in order to save
energy with an underfloor heating system. It is therefore interesting that in the measured
houses it is only one (Underfloor heating 2) out of four residences with underfloor heating
that has an average temperature which is significantly lower than for the once using radiator
systems. This would then mean that the three other residences with underfloor heating use
more energy than the once using radiator systems. It could be that the residence with the low
temperatures is the only measured residence with a properly working underfloor heating
system. It could also be that the residents in the three other houses does not know how to
control the heating system or believes/wants the indoor air temperature should/to be this
high. Either way it is a result that speaks against the use of underfloor heating systems. On
the other hand measurements should be performed in more houses to ensure this finding.
The ability for the different systems to adapt to changing conditions is worse with the
underfloor heating systems than it is with radiator systems with exception of Underfloor
heating 2. Even if this residence has on one occasion a very high peak in temperature (which
could have been caused by uncontrollable circumstances) it has the steadiest temperatures of
the measured residences. It is the complete difference with Underfloor heating 4 where the
indoor temperature varies very much even though it is the same kind of system. This
indicates that the comfort provided by an underfloor heating system can vary very much
depending on the residence and/or the residents. Changes in indoor temperature mostly
occurs quickly after changes in the outdoor temperature, the houses with radiator systems
adapts faster and stops heating quicker than the underfloor heating systems. This can be
because of the thermal storage in the foundation which is more used when using underfloor
heating systems and creates a more uneven temperature and higher peaks in the indoor
temperatures. Neither system seems to have problems when the outdoor temperature drops.
One could think that the underfloor heating system should control drops in the outdoor
temperature better because of the thermal storage even if this does not show in the measured
indoor temperatures. It could be that the radiators is faster to detect the falling temperatures
Underfloor heating- a solution or a problem
46
and therefore starts heating faster than the underfloor heating system, it would then use
more energy but keeps the temperature steady.
The average relative humidity of the measured residences does not differ much when using
underfloor heating systems or radiator systems, the exception being Underfloor heating 1
which has a lower average than the rest of the residences. It is surprising that Underfloor
heating 2 do not have a higher average relative humidity since it also has lower average
temperature and that the air therefore can carry less moisture. The reason for this could be
that there is less residents in this house, which leads to less moisture and heat production. It
could also be that this house and heating system is better built and/or controlled than the
others and therefore perform better. The latter probably being the most likely one. Even if
their lives less people or not in this residence it is adapted for the situation and is an
indication that underfloor heating systems can have a lower indoor temperature that is
steady and probably need less energy than radiator heating systems. As seen in the results of
the humidity measurements the outdoor relative humidity has a higher impact on the indoor
humidity than the indoor temperature does. When the indoor temperature rises it is common
in the measurements that the relative humidity does too, which as previously explained
means that there is another factor involved. The presence of people is probably that factor.
Using underfloor or radiator heating systems does not seem to affect the indoor relative
humidity significantly, at least they do not affect it in different ways. There are probably
other aspects in the building construction that affect the indoor relative humidity levels
more.
Simulations 4.4
According to information gathered in the literature study it is required to lower the indoor
temperature in order to decrease the energy use when using underfloor heating systems. As
seen in simulation results in chapter 3.3.1 this is not the case when comparing underfloor
heating with radiator systems, even if the indoor temperature is set on 24°C the underfloor
heating system has a lower annual energy need than the radiator system. As stated in chapter
1.2.1 underfloor heating systems should allow an indoor temperature 2-3°C lower than when
using a radiator system. That would then mean that if a radiator system has a heating set
point on 22°C the underfloor system should allow 20°C.
Underfloor heating- a solution or a problem
47
Figure 4.1 Difference in annual energy use for radiator (22°C) and underfloor heating (20°C)
When comparing the annual energy use of these cases there is (as shown in Figure 4.1) a
grave difference between the two systems. According to the results from Design builder the
underfloor heating system would only need 87% for a well-insulated house and about 81%
for a badly-insulated house of the energy that is needed for the radiator system. This result
speaks against the belief that underfloor heating systems would not be suited for well-
insulated houses and implies that this system is energy efficient. It seems like, according to
Design builder, that underfloor heating is a superior heating method in all conditions that
was tested in this study. Results from simulations does not necessary reflect the reality and
there is of course a chance that Design builder is exaggerating the impact of underfloor
heating systems. Another aspect could be that in the simulations the underfloor heating
system works and is used as intended, which may not be the case in real houses. The human
factor seems to have a big impact on how well the heating systems work and it seems like
the knowledge on how to control an underfloor heating system is not as well-known as for
other heating systems. As seen in Figure 3.5 residents that have problems influencing the
heating systems have more problems when using an underfloor heating system. It could be
that this kind of systems is harder to control since there are more factors that can influence
the control of the system. It could also be that it, compared to other systems, requires more
knowledge to install correctly and that this knowledge is not always known by the workers
installing it. Since it is on average (according to the respondents) easier to influence the
room temperature with underfloor heating systems it seems like the latter explanation is the
most correct one.
When it comes to the utilization of thermal mass the underfloor heating systems seems to be
better than the radiator system, this is no surprise since underfloor heating heats a larger
volume of potential heat storage. It does not seem like the indoor temperature drops or
varies more because of lack of thermal storage with an radiator system, this can be
explained by that radiator systems is quick to adapt to changing conditions and therefore
starts heating to avoid changing indoor temperature. This does that the radiator systems
3325 3431
6644 6787
0
1000
2000
3000
4000
5000
6000
7000
8000
Well-insulatedwith wooden
flooring
Well-insulatedwith tilled flooring
Badly-insulatedwith wodden
flooring
Badly-insulatedwith tilled flooring
Energy difference/(kW
h/year)
Underfloor heating- a solution or a problem
48
needs more energy compared to an underfloor heating system (as seen in chapter 3.3.2). The
difference in the ability to utilize the thermal storage between the two systems is lower with
a badly-insulated house. This is because the stored heat escapes through the foundation and
that the underfloor heating systemsâ radiated heat can be wasted the same way.
It is not tested in this thesis how the different systems would perform if there is zero
insulation in the foundation since this hopefully would not be the case in reality.
If using a heat pump in combination with the heating system it is possible to lower the
energy need of the system. It is even more efficient if using underfloor heating since the
temperature lift is lower with this system, which leads to a higher COP on the heat pump.
Underfloor heating- a solution or a problem
49
5 Conclusions
Residents with underfloor heating systems are on average more pleased with the
energy use, the thermal comfort and their residence as a whole compared with
residents with other heating methods.
Discomforting high temperatures and varying temperatures is perceived to be less
common during the heating season with underfloor heating systems than other
systems. Draught is perceived to be slightly more common during this time period.
It is perceived that too cold temperatures during the winter period occur more
often when not using underfloor heating. The perceived temperature during
winter when using an underfloor heating system is very close to the wanted
temperature.
Varying room temperatures during temperature changes outside is perceived to be
common with underfloor heating, the reason for this is the utilization of thermal
mass which creates a delay before the system stops heating the room. Despite that
it is perceived to be easier to influence the room temperature when using this
system compared to others.
Wood/wood parquet and tiled flooring is the most common flooring materials
when using underfloor heating. Residents with heavy flooring materials that store
a lot of heat have more often problems with varying indoor temperatures.
An underfloor heating system can lower the indoor temperature and thereby have
a lower energy need than other systems. For this to be true the system has to be
installed and controlled properly, which is not always the case.
Residences with underfloor heating systems have a more varying indoor
temperature than residences with radiator heating systems, according to the
measuring study in this thesis.
Changing outdoor temperatures have a greater influence on the indoor
temperature when using underfloor heating systems compared to radiator heating
systems.
The utilization of thermal storage helps to lower the energy need when using
underfloor heating system during the heating season. This system also utilizes
added thermal storage better than radiator systems.
Underfloor heating- a solution or a problem
50
Underfloor heating- a solution or a problem
51
6 Future work
In order to see if the conclusions in this thesis are accurate it would be interesting
to see questionnaire studies and measurements from other locations.
More research on heating systems in combination with heat pumps or solar
collectors would be interesting to see, since this could change which systems that
is the more energy efficient.
Different energy supplies could influence the energy efficiency of the system,
testing this would therefore be important.
Since the main heating systems in this thesis were underfloor heating and radiator
systems it could be interesting to see comparisons with other systems.
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Available at: http://www.stat.fi/til/asen/2013/asen_2013_2014-11-14_tie_001_sv.html
[Accessed 20 05 2015]
T2, 2002. Handbok för varma, sköna golv. [Online]
Available at: http://www.aeservice.nu/pdfer/gv_handbok.pdf
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Appendix A
Hej!
Det stÀlls mer och mer krav pÄ framtidens bostÀder. Man tar fram nya metoder för att
vÀrma upp vÄra bostÀder och fÄ ner energianvÀndningen sÄ mycket som möjligt. Det Àr
viktigt att detta sker pÄ ett sÀtt dÀr bostadens inomhusklimat inte pÄverkas negativt.
För att kunna förbÀttra framtidens bostÀder behövs mer information om hur de boende
upplever sitt inomhusklimat. DÀrför skickar nu Lunds Tekniska Högskola ut denna enkÀt till
Er med syftet att undersöka vad ni tycker om er bostads inomhusklimat. Era svar kommer
att anvÀndas som grund till framtida arbete med utveckling av energieffektivva
uppvÀrmningsmetoder.
Era svar Àr mycket vÀrdefulla för vÄrt arbete med att utveckla framtidens bostÀder!
Stort tack för hjÀlpen!
Student AvdelningsförestÄndare
Joakim Larsson, Ing. Dennis Johansson,TeknDr.
Appendix B
1. Hur mÄnga personer bor i bostaden?
RÀkna med alla vuxna och barn som bor i bostaden minst hÀlften av tiden.
1 ⥠Vuxna (18 Är och Àldre)...... personer
2 ⥠Barn 13-17 Är .................... personer
3 ⥠Barn 0-12 Är ....................... personer
2. a) Vilket Àr husets ungefÀrliga byggnadsÄr?
Ă r
b) Vilken typ av hus Àr det?
1 Radhus
2 Kedjehus
3 Parhus
4 FristÄende villa
5 Annat
c) Hur mÄnga vÄningsplan ovan mark har huset?
1 1
2 1 œ
3 2 eller fler
d) Hur Àr det huvudsakligen grundlagt?
1 Betongplatta pÄ mark
2 Torpargrund/krypgrund/plintgrund
3 KÀllare/souterrÀng
4 Vet ej
3. Ăr du nöjd med din bostad som helhet?
1. ⥠Nöjd 2. ⥠Ganska nöjd 3. ⥠Varken/eller 4. ⥠Ganska missnöjd 5. ⥠Missnöjd
4. Hur nöjd eller missnöjd Àr du med bostaden vad gÀller.....
Nöjd Ganska nöjd Varken/eller Ganska missnöjd Missnöjd
A Storlek? ⥠⥠⥠⥠âĄ
B Planlösning? ⥠⥠⥠⥠âĄ
C Dagsljus? ⥠⥠⥠⥠âĄ
D Trivsel? ⥠⥠⥠⥠âĄ
E Bostadskostnad? ⥠⥠⥠⥠âĄ
F Energiförbrukning? ⥠⥠⥠⥠⥠5. Har du de senaste 3 mÄnaderna kÀnt dig besvÀrad av nÄgon eller nÄgra av följande
faktorer i din bostad?
Ja ofta (varje vecka) Ja ibland Nej aldrig
A Drag ⥠⥠âĄ
B För hög rumstemperatur ⥠⥠âĄ
C Varierande rumstemperatur ⥠⥠âĄ
D InstĂ€ngd (âdĂ„ligâ) luft ⥠⥠âĄ
E Torr luft ⥠⥠âĄ
F Obehaglig lukt ⥠⥠âĄ
6. Hur tycker du att vÀrmekomforten i stort sett Àr i din bostad?
Mycket bra Bra Acceptabel DÄlig Mycket dÄlig
1.⥠2.⥠3.⥠4.⥠5.⥠7. BesvÀras du av att du i bostaden har...
Ja ofta (varje vecka) Ja ibland Nej aldrig
A alltför kallt pĂ„ vinterhalvĂ„ret? ⥠⥠âĄ
B alltför varmt pĂ„ vinterhalvĂ„ret? ⥠⥠âĄ
C alltför kallt pĂ„ sommarhalvĂ„ret? ⥠⥠âĄ
D alltför varmt pĂ„ sommarhalvĂ„ret? ⥠⥠âĄ
E kalla golv? ⥠⥠âĄ
F drag frĂ„n fönster? ⥠⥠âĄ
G drag frÄn ytterdörr? ⥠⥠⥠H varierande rumstemperaturer vi d
temperaturvĂ€xlingar utomhus? ⥠⥠âĄ
I svÄrigheter att pÄverka rumstemperaturen? ⥠⥠⥠8. Vilken typ av uppvÀrmning finns huvudsakligen pÄ bostadens bottenvÄning?
1. ⥠Vattenburen radiatorvÀrme 5. ⥠GolvvÀrme - vattenburen
2. ⥠El-radiatorer â Ă€ldre typ 6. ⥠GolvvĂ€rme - el
3. ⥠Elradiatorer â oljefyllda 7. ⥠Annat
4. ⥠LuftvÀrme, dvs varmluft cirkulerar i huset 8. ⥠Vet ej
9. Vilken typ av uppvÀrmning finns huvudsakligen pÄ bostadens ovanvÄning?
1. ⥠Vattenburen radiatorvÀrme 5. ⥠GolvvÀrme - vattenburen
2. ⥠El-radiatorer â Ă€ldre typ 6. ⥠GolvvĂ€rme - el
3. ⥠Elradiatorer â oljefyllda 7. ⥠Annat
4. ⥠LuftvÀrme, dvs varmluft cirkulerar i huset 8. ⥠Vet ej 8. ⥠Har ingen
ovanvÄning
10. Vilken typ av uppvÀrmning finns i bostadens vÄtrum?
1. ⥠Vattenburen radiatorvÀrme 5. ⥠GolvvÀrme - vattenburen
2. ⥠El-radiatorer â Ă€ldre typ 6. ⥠GolvvĂ€rme - el
3. ⥠Elradiatorer â oljefyllda 7. ⥠Annat
4. ⥠LuftvÀrme, dvs varmluft cirkulerar i huset 8. ⥠Vet ej
11. Om det finns golvvÀrme pÄ bostadens bottenplan, vilket golvmaterial ligger ovan det?
1 Linoleum
2 PVC-/plastmatta
3 HeltÀckningsmatta
4 Plastlaminat
5 TrÀ/trÀparkett
6 Klinker
7 Sten
8 Annat material
9 Har ej vÀrmegolv
12. Om det finns golvvÀrme pÄ bostadens övreplan, vilket golvmaterial ligger ovan det?
1 Linoleum
2 PVC-/plastmatta
3 HeltÀckningsmatta
4 Plastlaminat
5 TrÀ/trÀparkett
6 Klinker
7 Sten
8 Annat material
9 Har ej vÀrmegolv
13. Finns fönsterventiler i sovrum/vardagsrum?
1 Ja
2 Nej
14. Hur sker tillförseln av vÀrme till huset?
1 FjÀrrvÀrme/central vÀrmepanna för omrÄdet
2 VĂ€rmepanna i huset
3 Annan
4 Vet ej
15. a) Hur ofta vÀdras det vanligtvis under uppvÀrmningssÀsongen (d.v.s. september-
april)?
1 Dagligen/nÀstan varje dag
2 UngefÀr 1 gÄng i veckan
3 NÄgon gÄng i mÄnaden
4 VÀdrar sÀllan eller aldrig
b) NĂ€r det vĂ€dras, sker det oftast genom att âŠ
1 ...ha vÀdringsfönster/fönster öppet hela dagen/natten
2 ...ha vÀdringsfönster/fönster öppet nÄgra timmar
3 ...ha korsdrag nÄgra minuter
4 VĂ€drar aldrig
16. a) Har nytt golv lagts in i bostaden under de senaste 12 mÄnaderna?
1 Ja
2 Nej
b) Vilken typ av golvmaterial finns i bostaden?
Flera alternativ kan anges.
1 Linoleum
2 PVC-/plastmatta
3 HeltÀckningsmatta
4 Plastlaminat
5 TrÀ/trÀparkett
6 Klinker
7 Sten
6 Annat
17. Hur varmt Àr det ungefÀr i bostaden under ....
VinterhalvÄret? SommarhalvÄret?
°C °C 18. Vilken temperatur skulle ni vilja ha i bostaden under...
VinterhalvÄret? SommarhalvÄret?
°C °C
19. Om vi har fler frÄgor angÄende ert inneklimat hade det varit bra om vi kunde komma i kontakt med er, ber er dÀrför fylla i kontaktuppgifter nedan (om ni absolut inte vill bli kontaktade sÄ bortse frÄn att fylla i).
Namn: .............................................................................. Telefonnummer:..........................................................
Dept of Architecture and Built Environment: Division of Energy and Building DesignDept of Building and Environmental Technology: Divisions of Building Physics and Building Services