We have a passive solar house with a sunroom built on the entire south face of the house. (Plans are at http://babel.hathitrust.org/cgi/pt?view=image;size=100;id=umn.31951p007429573;page=root;seq=156;num=147
if you're curious.) Between the sunroom and the main living space are three sets of French doors.
On the (admittedly rare) sunny days in a Michigan winter, the sunroom does get to a nice 65-75 degrees. Temps peak around 3pm then drop off pretty rapidly, especially in winters like this one where the thermal mass is quite cold. What would be awesome is if there were a way to open a door/vent/window into the living space when temps get over, say, 65, and then close it when it dropped back below 65.
Anyone have any ideas?
Major requirement: this can't let a ton of air through when it's theoretically closed. That's the problem I've seen with most greenhouse-type vents; they just don't really get airtight (or anywhere close) when they are closed. And, of course, you have to be able to shut off the auto venting in the summer when you're trying to keep the house interior cool.
Things that can change: The French doors could be replaced with some combination of operable windows/doors. I'd like to keep a similar amount of glass, though; the house is fairly dark to begin with and all the glazing is on the south side (into the sunroom), so I don't want to lose much of it.
Thanks for your ideas!