LEED for Homes Window SHGC

Sara Heppe

Architect

PF&A Design

LEEDuser Basic Member

11 thumbs up

November 16, 2012

I am working on a project in a zone 1 climate. Currently our house shows that it has a 34% window to floor area ratio (WFA). After doing the adjustment for SHGC for exceeding an 18% WFA, our final SHGC that we must meet is 0.14. First, do we need to find a product with an SHGC less than 0.14 to get credit? Secondly, most of our windows are placed in areas with deep overhangs. These windows will never receive direct sunlight no matter what time of year it is. Do we have to count the window area in the overhangs? Seems like if the intent is to reduce solar heat gain, then we would be able to omit these from the WFA calculation.

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Ann Edminster

founder/principal

Design AVEnues LLC

LEEDuser Expert

8 thumbs up

Thu, 03/28/2013 - 22:07

Your best bet is to adopt the performance approach (EA1) rather than the prescriptive approach. This will allow you to weigh and trade off a wide range of energy performance factors, choosing a package of features that provides synergistic outcomes. Optimizing for a single variable such as SHGC is a "dis-integrated" design approach. So while LEED for Homes does allow this path, I would personally discourage it.