Built in about 1 hours work from old windows. Temperature outside was in the 30s the green house is 70 degrees. I planted about 90 seeds tiny plants are starting to come up. Sun is low in the sky about 40 degrees it will be 34 degrees Dec 21 then the sun will start coming up higher in the sky. About end of January sun will be about 40 degrees again. March 21 sun will be at 61 degrees it will be above the trees and the little green house will be getting hot probably 90+ degrees in 30 degree weather. When that day comes windows will need to be gaped open to vent the heat. I picked up 4 more windows yesterday from the trash soon as I get 3 more windows the correct size I can double the length of the green house. Companies that install new windows throw about 100 old windows in the trash dumpster every day I picked a common size window this makes them very easy to connected together with only 2 screws on the edge. These windows came from a house built in 1945 they are in bad condition, caulking is falling off, paint is pealing off, I re caulked them just good enough to keep the glass from falling out but did not paint them. I might try to get 20 more windows to set up like a TeePee tent over a row of plant started from seeds so I can get them started a month early when it gets warm enough in spring there is no more frost I can move the windows away and stack them in a pile in the back corner of the yard. I found 2 aluminum all glass storm doors if I can find more of these doors they will make a good walk in green house. Even if you can not find windows all the same size they are still easy to piece them together.