zero carbon and sap
TRANSCRIPT
SAPs in Detail and Getting to Zero Carbon
Preparing for Zero Carbon Seminar February 2011
Claire Westron Rund Partnership Ltd
• Code for Sustainable Homes• Planning Policy requirements• Building Regulations Part L• SAP • Case studies
Local Authority Planning Policy
Southampton – Code Level 4 and 20%
Eastleigh – Code Level 4 and 15% energy from renewable sources
New Forest – Code Level 3 (4 from April 2012)
Bournemouth – Code 3 (from Summer 2012)
Winchester – “Policy Aspiration” Code Level 5 (Energy and Water sections only)
What is the future for Part L?Reduction in Carbon emissions overPart L 2006
Reduction in Carbon emissions overPart L 2010
Revisions to Part L
Code Level 3 25% - 2010
Code Level 4 44% 25% 2013
Code Level 5 100 100% 2016
Zero carbon
2016 zero carbon new homes policy includes only the emissions covered by Building Regulations (heating, fixed lighting, hot water and building services)
Emissions from cooking or from plug-in appliances will not be addressed as part of this policy.
Zero Carbon Hubwww.zerocarbonhub.org
Part L Consultation
What are the main factors affecting the SAP assessment?
Dwelling size, type and orientation
U-values
Thermal mass
Thermal bridging
Air Pressure Test
Ventilation
Heating, hot water and controls
New technologies
Thermal Bridging
Where two heat loss elements meet, there is the potential for heat to be lost via increased conduction
• Repeating e.g. timber studs dealt with in the U value calculation • Non repeating
3 possible specifications:
•Default y = 0.15
•All details conform to Accredited Construction DetailsSAP 2005 - default y = 0.08SAP 2009 - y value to be calculated by assessor
3. Details conform to another Government Approved Source
Air Pressure Test
• Test all dwellings
• example – 3 bed semi
Air pressure test
TER DER % improv
4 18.52 18.26 + 1.4%
6 18.52 19.35 - 4.5%
Ventilation
Key points
• SAP 2009 rewards MVHR less than SAP2005, making it easier to
achieve compliance with natural ventilation
• There is a huge variation in efficiencies of MVHR systems
• Where air tightness is better than 5, additional background
ventilation is needed
• Where as built air tightness is better than 3 the ventilation
strategy needs to be checked
Heating and Hot Water
• Gas / oil / biomass boilers
• Heat pumps
• Solar thermal panels
•Secondary heating e.g. wood burning stoves
New technologies
•Shower Heat Recovery Unit
•Photovoltaics
•Flue Gas Heat Recovery
•Wind turbines
•Hydro power
Case studies
1. 2 bedroom flat
2. 3 bedroom semi detached house
3. 4 bedroom detached house
Part L Code 4 Code 5 (2016)
U valuesWallsRoofFloorWindows
0.190.11n/a1.4
As Part L As Part L
Ventilation MVHR MVHR MVHR (improved efficiency)
Air pressure test 5 5 3.5
Thermal bridging Accredited Construction Details
Accredited Construction Details
Accredited Construction Details
Heating and hot water
Gas combi boiler Air Source Heat Pump
Communal biomass boiler to block
Renewable None None 0.7kWp PV
Type : 2 bed flat (57m2)
Shower Heat Recovery Unit
Improved hot water cylinder insulation
Enhanced Construction Details
3
MVHR (improved efficiency)
0.200.110.151.3
Code 4Part L Code 4 Code 5 (2016)
U valuesWallsRoofFloorWindows
0.220.120.151.4
As Part L 0.200.110.151.3
Ventilation MVHR MVHR MVHR (improved efficiency)
Air pressure test
4 4 3
Thermal bridging
Accredited Construction Details
Accredited Construction Details
Enhanced Construction Details
Heating and hot water
Gas system boiler Gas system boiler
Improved hot water cylinder insulation
Renewable None 1kWp PV 3kWp PV system
Type : 3 bed semi (85m2)
Part L Code 4 Code 5 (2016)
U valuesWallsRoofFloorWindows
0.240.170.171.4
As Part L As Part L
Ventilation Natural Natural Natural
Air pressure test 7 7 7
Thermal bridging Accredited Construction Details
Accredited Construction Details
Accredited Construction Details
Heating and hot water
Gas system boiler Gas system boiler Biomass boiler (wood pellets)
Renewable None 1.2kWp PV 1.6kWp PV
Type : 4 bed detached (125m2)
Future changes to SAP• Thermal bridging - 19 more junctions to
consider• Degree of pipe insulation• Changes to carbon emission factors• Revisions to solar radiations (changing outputs
from PV and solar thermal)• Lower default efficiencies for heat pumps
Claire Westron
Code for Sustainable Homes and SAP Assessor
email: [email protected] tel: 023 8062 3750