Posted: 24/09/2013 at 18:08
Don`t waste your time with gas heaters. Buy an electric GH thermostatically controlled heater which will not cause condensation or any other problems. Depending on what you are growing in late autumn/winter/early spring, keep the thermometer to about 45 degrees which will keep the cost down. I use my heater from mid March to mid May for my tomatoes, rooted cuttings of Pelargoniums, Penstemun and seedlings of Cosmos, etc. with the temperature around 55 degrees.
I find the extra electricity increases the monthly cost of about £10 per month - not too bad. Gas, like Paraffin, requires the dirty job of cleaning the wick or changing the gas canister often at inconvenient times.