Will it Work?

[lakngulf]

Or too dangerous? I need a better source of heat in my greenhouse. I am considering using this old fireplace insert and convert it into a free standing stove. Of course, I will have to cut away some of my work space, and will have to attach a three wall pipe flue, using a rectangle to round transition piece. Also, I am thinking that some three foot protective walls on three sides would be helpful. Will it work?

 

[dave1949]

Pretty big stove for the space.

Have you considered a direct vent (no outside vent) propane fired heater? You get some advantages, especially in a greenhouse:
1) Thermostat control - works when needed whether you are there, awake, or not.
2) No tending of a fire.
3) No cutting firewood.
4) Produces lots of by-product humidity from the burning gas.
5) Adds CO2 to the air, a plant accelerator used in commercial greenhouses.

 

[Gunny]

I'd have to go with Dave on this one, the non vented LP heaters can be found new for just less than $100, and if you're buying triple wall pipe, you'll spend that much or more on just the pipe, plus all the work installing the woodstove.

The LP heaters thermostat would do a much better job of maintaining even heat, the stove would probably heat too much at times, or not enough if left to burn out, and it would work much better with the solar heating coming through those windows siding, the stove would keep on chugging.
No mess to clean up, no firewood to split and haul in. While your firewood may be free, I still think the advantage goes to the LP heater.

 

[Ted Summey]

+1 on the LP heater. The wood stove will create a drying effect in the greenhouse plus it will require constant tending to avoid temperature swings. LP is almost set it and forget it.

 

[forgeblast]

What about a solar air heater. We used one on our house for a year. It worked pretty well. you dont even need power to run it. If you look up builditsolar.com you will see gary's write up in mother earth news.

 

[ericb2400]

The dw uses a cabose stove to heat her greenhouse. She starts a fire after sun down and it keeps it warm all night. For the lack of moisture, she puts a pot of water on the stove. It must work we have green peppers and tomatoes all winter.

 

[lakngulf]

The dw uses a cabose stove to heat her greenhouse. She starts a fire after sun down and it keeps it warm all night. For the lack of moisture, she puts a pot of water on the stove. It must work we have green peppers and tomatoes all winter.

Yeah, now that's what I want to hear....Just kidding. I do have Propane gas in the greenhouse, but with a 100lb tank. It lasted two seasons, but (1) I was stingy with it (2) I did not know when it was going to run out and (3) I am using an old heater that is not thermostat controlled. I still plan to have it available for the "just a little bit" nights. I have lots of wood, and want to use the insert if it will be safe enough, and not be too much heat for the greenhouse.

Another note: I did not try to use the propane to keep it warm enough for tomato and pepper production. I would if I had wood. And, it would be good to get a thermostat LP heater as a catch all when I forget to fire up the wood.

Thanks for your comments.. More?

 

[dave1949]

How much does the insert stove weigh? Any rough guess? Are the fire bricks in good shape? I think inserts are often lined with fire brick.

If you use the insert, the heat shielding across the back and on two sides could be masonry, like bricks, something that would absorb and radiate heat over a period of time.

 

[lakngulf]

How much does the insert stove weigh? Any rough guess? Are the fire bricks in good shape? I think inserts are often lined with fire brick. If you use the insert, the heat shielding across the back and on two sides could be masonry, like bricks, something that would absorb and radiate heat over a period of time.

It is pretty heavy, but I think just metal. I can get it onto a hand truck, and can move one side at a time, but no lifting.

 

[dave1949]

The heavier the better I think, it should hold heat pretty well. Sounds like a solid insert.

I suppose if you have the space, you could build the equivalent of a fireplace to stick it into. That ought to store some heat overnight if you fire it up in the evening.

If you could do that in a central area of the greenhouse, that would be most useful. The fireplace could have some brick/stone benches on three sides for seed starting or plants that like to be nice and warm.