Best small greenhouse heating?

[Dollythehun]

Just be sure then, that you can set it that low. Ours wasn't that adjustable (and it was far more expensive).

[Roberta]

Originally Posted by Dollythehun

Just be sure then, that you can set it that low. Ours wasn't that adjustable (and it was far more expensive).

I have the exact heaters that I recommended. And have used them. Very efficient - the larger one, with the 20 lb. cylinder, really does give close to 90 hours.Of course, it is adequate only for a small greenhouse with outdoor temperatures that stay above freezing. A larger GH would need a larger - and hungrier - heater.

Here are some nifty calculators:
ACF Greenhouse Heaters & Heater Size + Cost to Heat Calculators
ACF Greenhouse Surface Area Calculator

[SaraJean]

Thank you all so much for the responses! This is my first foray into greenhouses and I know next to nothing about them. I went to Aces hardware and talked to them about the plug in heater and got a proper extension cord that can handle the load. So far so good, the wiring in my house had been redone about 5 years ago so the circuits are ok. This going to be a temporary fix as I ordered a Mr. Heater Portable to try out. Im going to have to keep a close eye on the temperatures once I start using this and figure out a way to regulate it from getting too hot. I also put 3, 5 gallon water storage containers in there to hold some heat but we haven’t had a stich of sun in 3 days so I haven’t been able to really see how these work. Nevertheless, all excellent suggestions and I really appreciate it!

---------- Post added at 05:35 PM ---------- Previous post was at 05:32 PM ----------

Perfect timing too, we might actually see some snow tonight or tomorrow

[Roberta]

When I was using that Mr Heater, it was to supplement the electric heater that could not maintain temperature on the really cold nights that went near 32 deg F (I was just trying to maintain 52-54 deg F. never mind 60 deg) So then, of course, if it got warm, the electric one just turned off... the propane one was gentle enough that I never had the GH overheat (just put it on "Lo") . Also, if you have a fan going, the heat gets distributed... on general principles you don't want hot spots - or cold spots. If you're going down to freezing or below, I doubt that you're going to have to worry about "too much heat", since I suspect that your little GH doesn't offer much insulation, but keeping that air moving is really important.

If your experience is anything like mine, you'll fight it this winter... and next year do it right, with a permanent GH and a built-in gas heater on a thermostat. (I can advise from experience on that when you get to that point)

[lidavis2110]

Mr. Heater Buddy fills my greenhouse with warmth. It works on propane and doesn’t require connection to electricity, that’s why it can run during power outages. But, you have to replace the fuel tank after several hours of use. It will run approximately 3 hours on High settings and 6 hours on Low. But the room heats up pretty fast. Here, I found a proper review on it Best Greenhouse Heaters - In-depth Review | (Mar. 2020)

[Dollythehun]

We tried that unit. We were unable to regulate the temperature accurately. How was yours calibrated? Ours wouldn't go low enough for our just above freezing winter use.

[Ray]

I think that, in general, radiant heaters aren't the best for this application.

The radiated heat is intended to strike a dense object (a body, for example), warming it. Air, being not so dense, doesn't heat appreciably, so the energy is not evenly distributed throughout the structure.

[Roberta]

Originally Posted by Dollythehun

We tried that unit. We were unable to regulate the temperature accurately. How was yours calibrated? Ours wouldn't go low enough for our just above freezing winter use.

Mr. Heater? It doesn't "regulate"... when I used it, I was just trying to keep the GH reasonably warm overnight in a serious (for southern California) cold spell. I'd see it as a backup to avoid disaster, rather than a primary heat source.

[Dollythehun]

I used one also. The thermostat was not able to be adjusted accurately. I wanted to keep the house at 40f to overwinter and it would not go down that low. I resorted to a "milkhouse heater" and a chicken brick.