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TRANSCRIPT
Retrofitting for Energy Efficiency
Achieving SuperGreen in an Existing Home
Northern Energy Solutions Conference
Whitehorse, YukonFebruary 17, 2010
Doug MacLean, P. Eng., MBA
Payback
Payback is defined as:
The cost of the project
The annual savings
For example:
Payback = $1,000 insulation retrofit cost
$200/year annual fuel saving
Payback = 5 years
R-50
R-40
R-20
R-10
R-20
Sample alternatives …
R-50
R-30
R-40
4
10
15
Payback <1 year
Savings 90% of best case
Payback 1.7 years
Savings 93% of best case
Payback 2.3 years
Best case
R-20
R-0 (no insulation
)
R-30
In order of payback …
R-50
R-0 (no insulation
)
R-0 (no insulation
)
1
2
3
Payback 0.3 year
Savings 86% of best case
Payback 0.4 years
Savings 90% of best case
Payback 0.7 years
Savings 92% of best case
ResultsWhen using a convection heating system
� Adding basement wall insulation has a short payback period
� Adding under-slab insulation is cost-effective for new construction
� Where possible, adding under-slab (or over-slab) insulation should be considered to improve comfort in winter
ResultsWhen using an in-floor heating system
� Adding basement wall insulation has a short payback period
� Adding under-slab insulation is cost-effective for new construction and improves comfort
� The reduction in the annual heat loss with addition of under-slab insulation is greater when an in-floor heating system is used.
Foundation Exterior Horizontal Insulation
� PaR-30
8
R-30
R-20
R-20
17
R-10
Heat loss change: nil
Payback: longer
Observations
� Reduction in heat loss: nil (<1%)
� Change in payback: longer
Result
� Adding insulation “wings” at the foundation footing is not worth doing (with or without under-slab insulation regardless of foundation type)
Soil Conductivity
� Increasing the soil conductivity from 0.8 W/mK to 1.8 W/mK increased heat loss by 3571 kWh on an uninsulated basement floor slab
� If the floor slab is insulated with R-20 insulation, the increase in heat loss is only 585 kWh
Result
� Greater insulation in the floor slab minimizes the influence of soil conductivity
Insulation Location
� Installing half the insulation on the outside of the foundation, and half on the inside resulted in less than a 1% reduction in heat loss compared to insulation on the inside wall only.
Result
� Basement insulation could be put in either location with little effect on energy use. Thus the choice of insulation location would depend on the cost of each alternative at the time of construction.
Summary of Alternatives
The insulation alternatives considered were:
� Furnace and in-floor heating
� Concrete and preserved wood foundations
� Soil conductivity
� Basement wall and under-slab insulation
� Horizontal insulation at the foundation footing
Conclusions
� Adding basement wall insulation has a short payback period
� Adding under-slab insulation is cost-effective for new construction, improves comfort and reduces the effect of soil conductivity
� The reduction in the annual heat loss with the addition of under-slab insulation is greater when an in-floor heating system is used and thus more important then.
Conclusions (continued)
� Adding horizontal insulation at the foundation exterior is not worth doing
� Even a high level of basement wall and under-slab insulation has a short payback compared to uninsulated basement walls
For more information:
Check our websites at:
www.esc.gov.yk.ca
and
www.housing.yk.ca
or call:
Energy Solutions Centre: 393-7063
Yukon Housing: 667-5759