My two 10'x12' GH's are wrapped in 16 mil solar-blanket material and it is guaranteed to last for 10 years. The nice thing about solar-blanket material is that it allows (diffused) light to pass through along with infrared (heat), insulates (some) against cold penetration, but I made to hold the heat in. I still have to use two heaters in each GH though. We got down to 33 F this AM and are supposed to get down to 28F tomorrow AM.
