Correct roof overhang depth for proper solar shading
I used Sketchup to help determine how the solar path would fall on the house I am designing. How do I determine the correct amount of shading/sun?
With the window heights and overhangs I used in the model, at noon on June 21, the entire glazing of the south elevation windows are completely in shadow, but just barely. At noon on January 21, the glass is completely exposed. This seems, intuitively, to be the sweet spot. But should I tweak the overhang to get more shading in the summer months or, conversely, more sun in the winter months?
The house will be 52 degrees north (roughly between Edmonton and Calgary), Climate zone 7 (i think) with about 5,500 HDD annually.
Also, plan on Larsen trusses, triple-glazed windows, airtight as possible but not much in the way of thermal mass (wood framed floor, no tile).
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