Greenhouse heating cost?

[orion141]

Hi all,

So I have been toying around with the idea of a 8x10 green house (potentially the turner brightleaf 8x10 with twin wall polycarbonate) in my back yard. This would be a freestanding structure (not lean to). I live in Connecticut (south central ct in zone 7) and am concerned about heating costs. We have propane as our heating source for our hone and I was wondering if anyone could even ballpark potential heating costs for this type of greenhouse in my location (using a propane heater). I could bubble wrap in the winter, but would not be able to dig 3-4 feet into the ground for the base. Thanks in advance.

Orion

[Ray]

Greenhouse heating up north is the single, biggest expense. I kept my 14’ x 18’ Turner greenhouse at a minimum of 55F in southeastern PA, and I was on a $400/month annual budget to heat it with propane. It had been considerably lower when I used a separated combustion heater, but when that failed, knowing I was going to move, I bought a less efficient model.

I had retrofitted the structure with 8mm twin wall polycarbonate, and I wrapped all vents with sheet foam over the winter.

I’m afraid you’re going to have to find a different supplier though, as - if I’m not mistaken - Turner no longer manufactures greenhouses. They are/were in Goldsboro NC, which was hit pretty badly by Hurricane Florence flooding a few years ago, and they never recovered. I have driven by their facility a few times since, and it is now Turner Tank Manufacturing.

I have a greenhouse heater sizing calculator at my website that’ll help you decide on the proper heater, then with your fuel rates, you’ll be able to hone in on that a bit better.

[Shadeflower]

Hmm this has given me an interesting idea.

I've always wanted a greenhouse but being aware of what Ray writes it has always put me off. Keeping chickens is cheaper which is in fact what I opted for instead lol.
But I have an old storage shed that I don't use much.
I already worked out previously it would cost around £300 to fully insulate it so I'm thinking instead of a greenhouse that needs to be heated lots I could convert my storage shed, add a couple of LED lights and I'd have my "greenhouse" without the huge heating bill.

This has given me something to think about as a great potential to increase my collection in the distant future

[orion141]

Originally Posted by Ray

Greenhouse heating up north is the single, biggest expense. I kept my 14’ x 18’ Turner greenhouse at a minimum of 55F in southeastern PA, and I was on a $400/month annual budget to heat it with propane. It had been considerably lower when I used a separated combustion heater, but when that failed, knowing I was going to move, I bought a less efficient model.

I had retrofitted the structure with 8mm twin wall polycarbonate, and I wrapped all vents with sheet foam over the winter.

I’m afraid you’re going to have to find a different supplier though, as - if I’m not mistaken - Turner no longer manufactures greenhouses. They are/were in Goldsboro NC, which was hit pretty badly by Hurricane Florence flooding a few years ago, and they never recovered. I have driven by their facility a few times since, and it is now Turner Tank Manufacturing.

I have a greenhouse heater sizing calculator at my website that’ll help you decide on the proper heater, then with your fuel rates, you’ll be able to hone in on that a bit better.

Thanks Ray. Looks like ~10k BTU heater would be needed for an 8x10' greenhouse in my area (assuming a low temp of 0 degrees F and minimum temp in greenhouse of 50 degrees F). If that were to run constantly I would need ~3 gallons of propane per day (~$2/gallon currently for me). I am assuming bubble wrap and heat sinks in the form of water could help this as well as the fact that I imagine the heater would not run 24 hours per day for months straight.

Interesting regarding Turner, I had looked at their website, which is still available, so it is sad they went out of business. Do you have any other recommendations regarding greenhouse manufacturers/suppliers?

I like the idea of a lean to greenhouse in theory, but my house has wood siding and I don't think this is ideal for ~80% constant humidity.

[Ray]

Originally Posted by Shadeflower

Hmm this has given me an interesting idea.

I've always wanted a greenhouse but being aware of what Ray writes it has always put me off. Keeping chickens is cheaper which is in fact what I opted for instead lol.
But I have an old storage shed that I don't use much.
I already worked out previously it would cost around £300 to fully insulate it so I'm thinking instead of a greenhouse that needs to be heated lots I could convert my storage shed, add a couple of LED lights and I'd have my "greenhouse" without the huge heating bill.

This has given me something to think about as a great potential to increase my collection in the distant future

Great idea.

In my home in PA, my "local inventory" was in a walk-out basement. Like you, I seriously considered a swap, using the greenhouse for storage and doing the growing under lights in the basement. I'm sure it would have saved a bundle. I was about to "pull the trigger" on that when we decided to move south...

Originally Posted by orion141

Do you have any other recommendations regarding greenhouse manufacturers/suppliers?

I like the idea of a lean to greenhouse in theory, but my house has wood siding and I don't think this is ideal for ~80% constant humidity.

Sorry, home-built or Turner are the only brands I've ever had, however, I hear a great many kudos being given to Gothic Arch Greenhouses. One advantage they have over many designs is a one-piece, curved wall/roof. Fewer joints, less leakage.

I think you're right about a lean-to with wood, unless you put a barrier layer in-between.

[estación seca]

Keeping livestock like chickens in the greenhouse helps with heating. Of course you need to keep chickens away from plants.

[naturalistSean]

I've heard of people using solar pool covers on their greenhouses, but don't have any experience with it.

[Ray]

In my first "substantial" greenhouse, a 14' x 14' copy of a Turner design made with treated lumber and covered with 2 inflated layers of greenhouse poly, my "benches" were bread flats sitting on a dozen, steel, 55-gallon drums that I had painted black and filled with water + antifreeze (for the corrosion inhibition).

After several days of sunshine, they had built up enough warmed thermal mass that the heater hardly came on at all.

Of course, that was in SC, where it tends to be sunnier in winter than up in the northeast.

[Bayard]

I would consider a 3 or 5 wall polycarbonate greenhouse. BC Greenhouses have models with those options. It’s harder to cool and heat a smaller greenhouse, so the bigger the better.