Originally Posted by aruzinsky

I don't use the heaters in the summer and I don't want extra humidification in the winter because the extra moisture would end up as extra condensation on the inner surface of the polycarbonate panels thereby transferring heat to the panels and raising my heating bills.

No, a ventless gas heater won't produce nearly as much moisture as an atomizer designed for use in a greenhouse. I could prove it by calculating the gallons per hour of water produced by burning 30,000 BTU of methane but, at the moment, I am too lazy. You should know from your own experience that a wide open stove burner, which is about 10,000 BTU, won't raise the humidity in your kitchen nearly as much as a pot of water over low flame, about 1000 BTU.