In my office that faces south and has the same single pane aluminum frame windows and un-insulated walls. I have not had the heat on since 9:30 this morning (4 hours ago). The air temp is 68ºF air temp (started out at the same 64ºF but within 30 minutes of direct sunlight spiked up), but the real difference are the surfaces. The window is 72ºF! All the other surfaces are between 66ºF and 75ºF depending on how much direct solar energy they are absorbing.
Pretty phenomenal really, if I can build a house that captures as much of this solar gain through the south side as possible why still significantly reducing the thermal loss through the envelope, I will be laughing all the way to the bank.
At the last BCBEC AGM, the first presenter was from RDH where they had studied the effects of solar gain on energy use in dwellings. The end result was that solar heat capture, even in Vancouver!, made sense and resulted in lower energy demands. The sweet spot utilized overhangs to prevent overheating in summer and windows with a 50% SHGC and a thermal resistance of U 0.16. This resulted in 22500 kWh of annual heating cooling energy. This was a significant reduction (10%) over the baseline 24500 kWh that utilized only 20% SHGC and U 0.35 windows.
This all of course is only practical if you have south exposure sun available. I am blessed with unobstructed full sun from around 9:00 AM to 2:00 PM with a couple of sporadic additional hours in the afternoon during the winter months.
|Winter Sun will unfortunately be blocked from 2:00 PM til around 3:30 PM|