I am building a sauna. I may be able to include an old piece of plate glass -- a store window. How much heat lose would there be through a 4 foot x 6 foot piece of glass?
Could I use an old aluminum framed glass door?
What are the right questions to ask? If a piece of glass is 140 degrees of more on one side, and sixty on the other,will the glass break? Explode? Give us a nice view? [The view will be the rest of the crawl space, not the outside.]
I was going to put my heater near the wall that wll be glass. How much distance do I need?