Greenhouse heating suggestions?
 

Hello! I live in chilly NY and I have got my self an insulated harbor freight 10x12 greenhouse and am currently deciding what heater to go with now that fall is in the air. I am looking for a nice space heater that can do most of the heating however I was planning on getting a southern burner vented propane heater for when it gets really cold. What do you think? Does anyone on here have experience with the vented type southern burner and also what space heater should I use? thanks!! :):)

How about a Rocket Mass Heater? You could buy one or build your own, uses very little wood, burns clean. Cheap and efficient...just a bit of time and planning to build. :)

I have a Southern Burner and it works great.

And if you don't want to build the mass, you can build a pocket rocket.

Check out my thread on this subject. http://www.orchidboard.com/community...use-build.html

To take up less space in the greenhouse, you might consider a Williams Direct-Vent heater.

They mount on the wall, where they only stick 10" into the greenhouse, and the combustion air is drawn in from the outside, and then exhausted there, and interior air is passed through a heat exchanger. No loss of heat or humidity through a vent. You can order them through Home Depot, and get them delivered to your local store for free.

Thanks, Ray! If my RMH doesn't work, this is a great option.

In case, modern heat pumps make great heaters/coolers and carefully chosen it's about 25% of the use of electricity for conventional electric heating.

I have a novel suggestion which is working very well for me. Orchid roots are more cold sensitive than leaves. Why not put the heat where it is needed, and save energy? I did not have gas access, I do have solar panels. Rather than run an electric heater / fan combination I am using electric bench heat. I used roof / snow melting cable 3" spacing over heavy exterior grade plywood and built a concrete countertop (coils embedded in concrete) in place. The coils are connected to a thermostat and the bench gets very warm to touch. Orchids love this warm media even when the air temp is 40F. I have mine set at 60, and with the radiant heat / fan there is some air warming too. I also have a supplemental light on a timer which throws off some heat too.

I'd really like to see your schematics for this heating cable idea. I've calculated my needed BTU use at 19,200
Being disabled, a rocket stove is not an option.
And unfortunately, I don't have access to gas, or solar panels.

There are several instructional videos on construction of concrete counter tops on you-tube.
This is labor intensive and permanent, but requires no maintenance when done.
The BTU calculations are not valid in this case, as you are heating locally (root zone) not the air. Most likely air temps will stay above 40, but you can add a small electric space heater (1500 Watt) to boost air temps if they drop below that. Snow melting cables are readily available on E bay and several other suppliers, similar cables are sold for soil heating and are the same thing. They typically run 5 Watts / foot are available in various lengths (plan ahead, there is no splicing allowed) and are water proof, so safe in the greenhouse, even if concrete cracks. Stretch- Run the cable around short wood screws, on 3-4" spacing cover with a light wire mesh, then pour concrete in place. Mine are 3" and top is very warm, but not to warm for roots. 4" will use less energy, and likely be adequate and less $. I based the heating coild density to be similar to electric floor heating used in homes. Isn't it nice to walk on a warm floor?? Orchids think so too! I chose not to use indoor products due to water proofing concerns. I use an adjustable plug in thermostat and run two zones. I'm using 1200 Watts on 20ft of bench.

The advantage is electric, clean, and no effect on humidity. Installation must be very sturdy, and you will need a contractor as even light concrete work is strenuous. Orchid roots grow right vigorously when kept warm like this.

Still you will want a very tightly sealed GH with double or triple wall polycarbonate panels to trap as much heat as possible, plus you need a fan to circulate air.

I have not found any electrical commercial products for this specific application.

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I hope my innovation works for others determined or limited to electric energy sources.
Good Growing.