No,. I haven't had to heat for a few years now. It will stay at least 10 degrees above outdoors temps. You are probably growing more tender tropicals than I am as well Karen.
I am afraid I may need to to provide a little heat this coming weekend as temps are dropping to low 20s. I use a micathermic heater with ceiling fan to circulate the rising warm air. If power is out, I do have a small wood heater to fall back on.
If we get snow, the polycarb roof panels will hold the weight of it and the snow helps provide insulation. I monitored the temperature in the greenhouse when we saw 4-5 inches of snow. It maintained it well. This much snow was not normal for here.
