The major difference between nat.gas and propane is, as you mention, cost and availability. In my area, propane is considerably more than nat.gas per btu. Both propane and nat.gas heaters can produce ethylene, carbon monoxide, etc if not properly installed, inadequate oxygen supply, or improper venting.

Thank you, cuestaroble. Do you know of a good source in any given area to determine what is easiest and cheapest to obtain, or could I just maybe ask at the local Home Depot?

Well, the other major issue, at least to me, is being able to run a propane heater off of a propane tank, as compared to having to run piping to a natural gas-fueled heater.

Ah. Not being terribly handy, that is sure relevant to me. Or, is the issue here more one of safety or permits?

Thanks,
Hilary

How big is your GH and how cold does it get?

I only have a single layer of plastic/glass windows up and have some decent size air leaks I still need to take care of. It got down to 27 last night but a 1200 watt ceramic heater kept the temp up to 48.

Mike

Hilary,I went with propane because I'm so far out in the country we have No natural gas available.I'm under the impression that natural gas is WAY cheaper.I've never heard that nat gas is any more harmful to use than propane.I've had my greenhouse heated with propane for about 7 years-and have literally grown thousands and thousands of plants with no advese effects.The main reason I went with propane was out ice storms-and power outages that result.We normally lose power for 3 or more days every 2 years or so.But if that were not a concern you may be able to heat with electricity.The heaters are the same price-some models are set up for propane-some for nat gas.Mark

Slightly off-topic, but pertinent to greenhouse applications - the use of propane vs NG is a common debate on boating forums - more typically among sailors in cruising communities.

Propane was installed by the mfg of my last boat to fuel the on-demand hot water heater, cook-top and oven. This is the most popular fuel for boaters, since it's readily available around the globe. Some proponents of NG however, in spite of questionable availability, choose it because of it's safety, relative to propane - which is heavier than air. Therefore, the gas could settle in the bilges if a leak ever occurs, risking explosion.

Unless it is piped directly to the home as an underground utility, sources of NG are sometimes difficult to find. Additionally, if proper exhaust vents, auto-detect shut-off valves and propane sniffers are installed, propane is a very safe fuel.

We've never had any problems in the 25+ years of using it on our boats and if NG was not available, I would not hesitate to select it as a heating fuel for my greenhouse - if/when we ever build one.

I meant to mention the importance of propane tank storage to the above post - but was distracted. It is unsafe and illegal in most areas, to store propane indoors, including boats and greenhouses.

Our boat had a specially designed tank locker with a bottom drain vent to dispense gas - which due to it being heavier than air, would settle to the lowest levels, if a leak ever occurred.

It's very important to store the propane tanks outside of the greenhouse, if used as a heating fuel source.

archdiver-
Thanks for making that important point. I use an electric-powered, oil-filled, 1500 W heater as my main heat source in the winter, but have a propane heater backup. The heater came with a long supply hose -- and specific warnings and instructions -- to ensure that the tank is able to be placed outside the GH when the heater is in use.

Hilary-
The issue is simply that, even if you have gas at your house already, you would have to run code-complying piping, perhaps underground, to your GH. We're talking 100's to 1000's of dollars here, depending on the situation. And gas piping installation is not a project for an inexperienced person.

Thanks for the advice. I am thinking propane it will be. I have read in a couple of books about keeping the tanks outside, and read various posts here (and in the books) about the need for venting, even for vent-free heaters.

Mike, I don't have the greenhouse yet, but when I do, it will be a 6X7 one with twinwall polycarbonate. Given that, save for a lone tangerine, everything in it will be succulents, I plan on keeping the temps most likely at about 45-50. It's mostly (I am thinking) going to be for winter use, as my house simply cannot accommodate the many plants I seem to try to stuff in it.

Thanks again everyone.

Hilary

thank you all for your information. I have been "looking around" getting information while getting ready to put together a GH. I knew heat needed to be addressed and now I have a solution prior to getting there. I LOVE this web site!

From my research (I've just come across the same issue) it looks as though natural gas is cheaper but you have to be linked. We aren't but it reassures me to think that propane might be more environmentally friendly (see link below).

Here is a link that might be useful: Propane vs Natural Gas

My Palram hobby greenhouse sits on my deck only about 4 feet away from the ng hook up. According to any charts I've look at, I need about 14K btu's to heat this structure- does anyone have experience with a small greenhouse gas heater that they could share their do's and don'ts.? Many thanks for any help.

You will need Heat, Water and Electricity. Best if run underground.
Gas vs LP really depends on if there is gas on your proberty already, and will someone run it back to your greenhouse. If it is not on your property already, or at least out front of you home, it is not an issue. Gas Co may not be willing to run a line for a greenhouse, or it may cost too much to run the line from the street.
All can be found out by calling local gas co.
All that said, construction of any structure on your property by be subject to a building permit and that is where you may run into probelms. Some areas are more challenging that others. make a few calls to your town, township, local gov office.
Just a few things to ponder.
Have fun and show us photos