I have a solar passive house design and I'm a few weeks away from starting the build. I have a question about some window choices I've made. The window brand is Vantage Magnum. The windows in question face north-northeast and the prevailing winds are north-west. The build is in Canberra.
The architect has recommended awning windows throughout. However around the deck I've asked for double-hung windows because I don't want the rugrats bumping their heads into opened sashes. Even with the corner protectors they might do themselves a nasty injury on the aluminium frames.
The architect has explained some of the tradeoffs. The awning windows have a much lower air-infiltration (0.12 vs 4.75) so the double-hung windows will admit cold winter drafts. The architect also explained that summer ventilation isn't a problem with awnings because the airflow is due to pressure differences, not the shape of the windows. I can also see that stylistically the awning windows look pretty slick.
I pushed (very lightly) for double-hung windows in a few locations on the basis of not bumping into the sashes and the architect complied without argument, but he rarely argues. I'm wondering how much this will affect the solar passiveness. The house has no active cooling and only slab heating. I will ask the architect but I'd like advice from these forums as well. It's always good to hear more than one opinion.
There are 6 windows I've asked to change from awning into double-hung. The remaining 30+ windows will stay as awnings. The 6 windows in question are in high traffic areas where the awnings would open across walkways or directly onto the deck. Will awning windows really be that much of a hazard? Will the change in air infiltration matter all that much? I have no qualitative understanding of what "4.75" means in terms of drafts. Is that going to be cold and uncomfortable? Or is that only a few extra dollars per year on heating?