Dave,

That is what heats my greenhouse. We had several that we used for the sunroom until we got a gas heater in there. My DH wired it to a thermostat and it worked great in my HF. With the solar pool cover I was able to keep the greenhouse at 55 degrees with only about $30 extra on the elecric bill per month. I had to be a little careful with the watering but that was not too much of an issue.

Cindy

Electricity is probably not a good heating source for a greenhouse, mainly due to cost. Electricity produces 3400 btu/kilowatt hour. A gallon of propane produces 92,000 btu and cost approximately $2.18 per gallon in the Madison WI area. The same amount of electricity would cost $2.69 (at $.10 per kilowatt hour, and the local supplier is thinking of another increase). Natural gas would be about 30% cheaper than propane, if that is available.