Will my crawlspace help temper passive solar gain?
My wife and I are having a 2100 sf house designed based off of rough sketches I put together. We are building in Squamish BC, Zone 4C. I have a relatively simple east/west shape and simple shed roof design. I’m shooting for R30+ wall, R50 roof and am now doing my best to dial my designer back on his suggested window layout. He really likes glass and currently has the overall Window to Floor Ratio (WFR) around 30%.
I am basing my perspective on the house design somewhere between the ‘Pretty Good House’ and ‘near Net Zero’. I will likely have the house modelled shortly to get more firm numbers, but currently I have been using spec sheets from existing Net Zero Homes and other passive solar rules of thumb to guide my revision of the WFRs. I am trying to cut the overall WFR in half.
I should mention that I am more concerned about the negative impacts of too much south facing glass in the shoulder seasons and winter, than I am in achieving a perfect passive solar design. Really, I’m looking to have nice south views, with some sun tempering, without overwhelming the space with glare, overheating, and general comfort issues.
We have to build with a crawlspace to ensure our first floor joists are at a prescribed flood risk mitigation level, so my main question is, do crawlspaces help temper/absorb some of the passive solar gain? I have read somewhere that the 7% South glazing WFR value should be calculated including basement. How does a crawlspace influence the 7% south WFR number? Any other thoughts would be more than welcome!
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