Plastic Green House Film is a good choice for seasonal greenhouses, overwintering structures and high tunnels. Avoid construction grade material that has less strength. This film is warranted for 4 years or more and costs about double that of co-poly. It contains an ultra-violet stabilizer that reduces degradation.Plastic Green House Film is exposed to high UV radiation, heat build-up on the greenhouse supports, and the effects of crop protection as well as soil disinfection chemicals. Therefore, the films have to be stabilized with the right light stabilizers and UV absorbers.Plastic has better heat retention properties than glass, and less heat is lost through polycarbonate material than glass. This improved heat retention is key for the overall performance and effectiveness of a greenhouse.