Not using any Ken. What you see is the greenhouse material. I was going to buy a couple of the solar pool covers but decided to give a try to closing off the north ends. With the heater on low 9,000BTU/hr in the new one it was 35 outside and 52 inside last night. On the old one with the orchids I have the heater setting a little back from the tables I have them on but the temp difference was about the same.
