Optimum insulation depth
DouglasM4430
| Posted in Energy Efficiency and Durability on
I have seen UK documents online describing declining marginal thermal value as insulation depth is increased beyond an optimum. Please explain or suggest North American references.
I am located in Canada near Detroit – I believe climate zone 5.
Also, can you recommend energy analysis software for both new and energy renovations?
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Replies
BEopt is an easy to use software that will let you run as many scenarios with differing insulation levels as you would like.
Every time you double the insulation thickness, you cut the heat loss in half. So imagine a house where 1" of insulation would result in $4000 annual energy bills. 2" of insulation cuts energy use to $2000. 4" gives $1000. 8" gives $500. 16" gives $250. Etc.
For that first step, you save $2000 by adding 1" ($2000/in). For the last step, you save $250 for +8" ($31/in). Each time you double, there's half as much energy left to save and you're using twice as much insulation, so the value is four times lower