[MN Renovator]

The snow will melt off quickly if any sun manages to get through if I'm using plastic and even enough to do some work if I'm using glass since a decent amount of heat will pass through and melt it. Snow even manages to melt off the double pane skylight in the bathroom as enough heat passes through the skylight. Having something black an inch away will leave me clearing most heavy snowfalls off the glass but most lighter stuff will likely melt off. Plastic, even if its heavy might not stand the snow load. I'll wait until I can get some glass as the table saw that I have access to use is stored in a shed and it will unfortunately be a summer project for me. This winter hasn't been too cold yet so I'm not too missing out too much unless January is worse than last year.

I did some calculations on what the solar heat collection would be for a black 4x8 surface. I'm not believing the results though or that would have likely amounted to more heat than my furnace has produced so far this heating season. If that were the case I'd have excess heat but I think my math is wrong.

I was at a 'Living Green' expo and talked to a guy there that told me that the amount of heat lost out of glass, even if double or triple paned and well sealed makes the glass cost more than the solar energy than they allow through in Minnesota in December and January for the temperatures we get. Low SHGC on southern windows makes it worse as it blocks the sunlight that we need here. He said that anyone in MN with double pane glass with good condition glass shouldn't replace their current south facing windows with 'tax credit/energy star' glass as the cost to heat the house will go up more than it will cost cooling the house is there is a decent overhang or if the owner installs an awning or deciduous shade. I'm thinking that if a house built with smaller windows or low SHGC that glass outside the house would bypass this and allow for solar heating without having essentially an R2 glass assembly installed into a wall. With thermal mass, this all changes a bit because the heat during the day from a large glass assembly is absorbed and stays with the house which is why it works better to have more glass(almost all southern facing) in a passive house.