Posted: 01/09/2013 at 12:29
I started off with paraffin heaters, a long time ago, then progressed to propane gas, then to electric. Paraffin and propane burn to produce a lot of water and condensation which promotes fungal diseases. If you give it adequate ventilation, heat is going out through the vents. I can guarantee that on the night of the bad frost, it will run out at 3 am and everything freezes. When I had my last greenhouse, I had electricity piped up to it. An electric fan heater has none of the above problems, just the problem of the bill.
I should also add, that you need a qualified electrician, plug points suitable for outside use, and circuit breakers fitted as well. I have a master switch in the garage to isolate the greenhouse and pond pump if necessary.