Short answer, no. But I don't know how many heater cables you have.

Your GH surface area is around 1150. Using a standard GH heat calculator, assuming minimum of 40F, down to -20 (and I bet you get lower than that), with 2x wall PC, you need around 50000BTU. That heater only provides 19000BTU. That heater will keep your GH at around 8-10F when it drops down to -20. You need to double the BTU at least.

I am zone 5b/6a old map, solid 6 new map, and I keep my GH (same size or just a little bigger) in the upper 50s with around 58000BTU of heater output.

Here is a link that might be useful: GH heat calculator

Thank you stressbaby. After I posted this I happened across a gh heater calculator and came up with the same BTU's as you've indicated. I would really like to use electric (I could use propane but would need to add a large enough tank). The prices are horrendouse for an electric heater with 50,000 BTU's. :(

I just got the same heater for my greenhouse.. It's red right? My greenhouse is smaller, but i think it will heat the GH pretty well!! I guess the only way to check and see if it works is test it one night, as long as you have a heat source for backup in case the temp falls below the desired setpoint! Good luck, hope it works out.. i haven't installed mine yet!

How do the rest of you heat your greenhouse. I've been researching different heaters and am not sure what to do. I have my greenhouse almost completed and I am getting a bit worried about how I am going to keep it heated. The electric heaters that heat 50,000 btu's are very expensive and I wonder how much it will cost to run them?

I did a local search for used heaters and I found one that is a kerosene heater (118,000 btu). Can these be used in a gh? Also, what does one do if you are away from home for a time period? I don't know much about kerosene heaters but I assume they run out of kerosene quickly not? Also, is kerosene expensive?

Please.....help.

Mine is a lean-to (door connected to living room), it's about 12'Lx12'Wx21'H, i switched between 2 kerosene heaters. On the nights when it would only go down to 20F, i would use the 10,000 BTU heater. On medium would keep it about 45F-50F, when it would get colder I would use the 20,000BTU kero heater and on medium would put it around 50-55F, give or take depending if there is wind.. You just have to be careful, because if the GH is airtight, combustion will be poor and it will stink. Also, I was getting tired of filling up the Kerosene cans every week or so. You may want to crack open a window just so there is a transfer of oxygen. The plants weren't affected by the kerosene to my notice... but you have to try it and see. I like to open the door into the living room to let the heat in on sunny winter days but it would have the kerosene smell, it was nauseating. I just purchased a Dayton 240V heater, didn't install it yet, but i am confident it will suffice. So far the outside temps have been in the 80's and 60s-70's at night, so there is no need for heat yet!! Good luck, let me know if you have any questions.

Combustion heaters are a great big can of worms on this forum. Search the forum for "vented" or "unvented" heaters to review the annual winter debate.

Kerosene can and has been used in greenhouses. You will want to review the +/- of the different kinds of heaters before you make a decision.

I use a pair of 24000BTU vented Empire heaters and back that up on the very coldest nights with a pair of little electric milkhouse cheapos from WM.

SB

Thank you for the information fl50dude and SB. I did some research on kerosene heaters and I don't think I want to mess with constantly filling the kerosene tank. I see you feel the same way. My husband and I were thinking of getting a big tank and connecting a line to the heater but then I would still have that smell.

SB I googled Empire heaters and it appears as though they are natural gas or propane. Which do you have?

After reading as much as I can online I think my only two viable options are:

1. An electric heater with 50,000 + btu. (preferred)

2. A propane heater with 50,000 + btu and purchase a large propane tank and set it by my gh. The only problem with this option is where the gh is sitting, it would be hard for a propane truck to fill it during the winter.

I really appreciate hearing what you two do for heating. Thank you for taking the time to post your heating unit information.

I will send a photo if I can figure out how to do that in another post. ;)

Ladylotus, ND has some of the most brutal winters in the USA, so it's going to be expensive to keep that greenhouse at 40F. If I did my math right, 50,000 BTU/hour is the same as 15 Kilowatts. Let's say you are paying 10 cents per kilowatt-hour. $0.10 x 15kw x 24 hours per day = $36 per day, or roughly $1100 per month. And 50,000 BTU may not be enough.

I don't try to heat my greenhouse in winter. I move my plants into the basement and grow them under fluorescents in the winter. The heat from the fluorescents helps keep the house warm. Would this work for you?

New to forum, so appreciate your patience! Moved to NC from Florida last year with tropicals, etc. Converted a lean-to garage into a GH (20x20) with an electric heater, supplemented with propane. After high electric bills and running to fill up propane tanks, we got smarter, I hope??

Put in a Vent-free blue flame gas heater + 100 gallon tank for this year. Any comments?

Jan22,

Are you referring to Natural Gas? I live in the country and I'm not sure if I have access to natural gas. Tomorrow I am going to check with a heating and cooling company in town to see what they suggest and how much it would cost for them to put a unit into my gh.

Our gas company recommended this for my greenhouse - it's propane, but the "blue flame" is "suppose" to be OK for plants. Cost upfront was a little high, but going over last year's expenses, I think I'll be better, if the plants survive :)