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Matt Rothenberg
Passive House enthusiast
Asked a question 2 years ago

We’re building a small house so our energy use is already very modest—how can we justify doing the other stuff to achieve the Passive House standard?

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David Salamon
Architect, CPHC - CPHD

You have to build an energy model in order to be able to justify your design decisions.  Do you need 1", 2", 4" of sub slab insulation?  How high performing do your windows need to be?  The only way to really know if you can justify the expenditure is to understand the options and the cost ramifications both in first cost expenditures and in long term savings and the way to do that is with an energy model.  I'm working on a project now where we are going to use low boy electric resistance water heaters instead of heat pump water heaters.  Even though the low boys are less efficient and increase the amount of PV we need, it is still the most cost effective option and we still achieve PH.  We wouldn't have been able to make an informed decision without the energy model though