Propane Heating

[littlefrog]

How many sq feet are you heating and what is your lowest outside temperature? That makes a big difference. If you are going to do electric, that is not a bad option, you just need to size the system appropriately. I think there are some newish 'baseboard' style electric radiators, which are oil filled or some such fancy technology. Low profile, pretty efficient, and quiet.

I'd definitely go with an oil-filled electric heater of some sort, they give much more consistent heat and I don't think they dry out the air as much. I use a portable one in my daughter's bedroom which works really well (plus it doesn't get so hot that it could seriously burn skin).

Another option to consider, since your greenhouse is attached. What do you heat the rest of your house with? Gas? Maybe you could add a zone to your central heating system. Hot water radiators? Add a couple of those. It might be a lot easier to add onto an existing system than to build a new one.

[Gin]

Here is what has worked for me in 2 different greenhouses . First there is no natural gas in my area so it is propane or nothing . My heater is vented as the other one was , It is an older one with a mechanical thermostat it will come on without electric power of course the blower won't run . We have a generator so it is not a problem .
I have read if the greenhouse is tight the ones that are not vented sometimes do not have enough oxygen and the heater will not come on, a safe guard thing . Gin

[kmcalpin]

My greenhouse is 10 feet wide, 24 feet long ( so I guess 240 square feet) although I only grow orchids on about 3/4 of the greenhouse. It can remain cooler on the other side for the pancake plants and cacti, also for the dracs and masdies I have in a terrariium on the floor.

the highest point in the ceiling is 10 feet. Minimum outside temp last winter was one morning it was -7 degrees F, but that is very rare. Usually it gets down to about freezing, and the sun heats things up extremely quickly in the AM. I will not need any heating in my greenhouse during the daytime hours at all, or if I do, extremely rarely.

We use gas for the rest of the house, NOT a bad idea! I like the hot water radiator idea thing too.

[Bradfo69]

I have to agree with km... This is slightly frustrating and scrapping the whole damn hobby crosses your mind occasionally! Or just grow Calanthes that you can toss in a box in the basement each winter.

I'm still in a holding mode but using a small electric heater for the time being. Maybe I can sneak out at night and run an extention cord to the neighbors.

I am almost convinced a new greenhouse grower should operate it for a year without plants and measure conditions on a daily basis rather than go through the stress of putting everything in this foreign environment.
The one thing I am pleased with is the perceived r-value of the walls on this thing. Granted it hasn't gotten really cold yet but it's been running much warmer than the ambient temp even at night without a huge drop off. And the little electric heater on it's lowest setting brought the air temp up 7-8 degrees in an hour or so last night.

I'll be posting pics soon.