Greenhouse: glass or plastic

I won't be heating it 24/7 until the beginning of March. Just too pricey. I bought a gas heater out of the US and converted it over to natural gas and I have a hook up to the mains a few feet away. I switch the feed back and forth in spring and fall between the bbq if I'm cooking, then back to the heater when not. It is a very fast unit. 10k BTU - and the greenhouse is only 300'cubed. I have a kerosene-believe you call it a parrafin heater -also but unfortunately they don't have thermostats and it was just too much for the small greenhouse and even too much for this one. It pumped the temperature in there up to over 90f in a short time and of course didn't shut off - stupid choice

 

Well you seem to have it covered Lori.
I heat mine all winter but only to 40f, and that can sometimes run out a bit expensive.
If I had to deal with anything like minus 23 I doubt my electric fan heaters would cope.

Neither would my wallet.

 

I tried heating it one year - didn't have the film on the inside, instead had bubble plastic that is meant for greenhouses which turned out to be less efficient and downright ugly. It cost me about 120 of your pounds just for one month That is when I quit doing that

As soon as the day temps are consistently above freezing I will then load it and heat it. That also coincides with our 12 hours of daylight and increasing...

I'm still pretty new to this gardening gig. Did pots of peppers for about 10 years but very little else. Then about 4 years ago I got the first greenhouse. I also built coldframes.. I guess I like tinkering as much as playing in the dirt.
This is one of the cold frames I built- using plexiglas and pvc. I filled in the other sides of the stairs this last fall with another when I recycled a french glass door.

 

Never worked out how much it costs me to heat my two greenhouses as the bill comes in under my domestic electric bill, but its probably closer to £30 a month in jan and feb.

12 hours of daylight, we are all waiting for that one.

 

Our natural gas is about 1/2 the price of electric heating. We get charged about 60p for a kwh. of electricity. Adds up pretty quick. And the rate drops a little between 7 at night and 7 in the morning so, even though gas is cheaper heating than elec., heating the greenhouse is still way more expensive than lighting. I have my propagators down in the cellar under flourescent lighting that runs for those 12 hours at discount rates. The lesser of two evils.

Plus it gives me some exercise going up and down the stairs

 

Instead of glass or plastic panes, would polythene sheeting be practical? My noobie logic says that if it's good enough for a polytunnel, it has to be okay for a GH - fact or fantasy?