Hoping some building science folks might have some good suggestions. I'm helping a contractor friend build out a yoga studio in a commercial space. The yoga that's going to be practiced there is hot yoga, more specifically Bikram which calls for a room temperature of 105 degrees (yes, you read that correctly. I actually practice Bikram and it's pretty great).
Anyway, he's got a good heating contractor on the job who's worked out getting the room up to that temperature without a glitch. We insulated the drop ceiling a great deal, as well as the walls, and the heating guy ran a baseboard backup system along the one exterior wall of the space to compensate for dropped temperatures due to the two aluminum-frame windows on that wall. We're trying to come up with a solution to minimize the heat-lost from those windows, as well as the condensation which we both surmise will be great once we hit late winter (we're in upstate New York, by the way). He's wondering about sealing the deep window jamb in with a big sheet of plexi-glass and I fear that doing so will just create another plane on which condensation will occur. We can't cap the aluminum frames from the outside as they're part of a strip mall and so won't allow varying the exterior aesthetic. So any solution we come up with has to happen from the inside.
Any ideas what we can do here to minimize heat transfer through the aluminum and window as well as deal with the condensation issue? The windows are about 6-ft. by 6-ft. and the window jam is about 12-in. deep.