greenhouse heating

awalker · #1 10-30-2009, 11:25 PM

Hi -- I am finishing up a new greenhouse and researching gas heaters. The Southern Burner C-1 non-vented heater seems to be a very good value and efficient to boot. Does anyone have experience with this heater? Are there combustion products that effect flowers?

Thanks

raybark · #2 10-31-2009, 11:42 AM

You are always better off with a vented heater.

Incomplete combustion of fuels (poorly tuned or dirty burners) can lead to the creation of exhaust chemicals that will cause bud blast and even kill your orchids.

I have heard good things about Southern Burners, but most folks go the vented way.

tenman* · #3 10-31-2009, 12:51 PM

I have a southern burner as backup for my GH; it works fine when I turn it on. Got it (unused) in a trade a few years back. Of course with no fan, you'll need fans in the GH to circulate the heat adequately. Or, just get a forced-air gas vented heater. The kind often used for a garage. I see used ones suitable for a GH on craigslist frequently for $50-$200, if you're not averse to used. New ones are going to run you $500-$800. My main heater is one taken from the bay for an RV in an old bank, sat in a storage barn 20 years after that. Works great! Cost: $0, and some heavy lifting.

richardb · #4 11-05-2009, 03:28 PM

I have used an unvented gas heater in one of my greenhouses for many years. The essential key is allowing fresh air to get to the burner so that it burns "cleanly", and ensuring that the burner is checked and adjusted properly and every year or so, just as one would a central heating system in the house. I have a tube going from outside the house to near the burner and leave a small gap with one of the vents to allow any exaust to escape. One thinks that heat would escape, perhaps a small amount does, but then I would never leave my greenhouse completely sealed for long anyway - that is unnatural for any plant. The heater runs on propane and my system works fine. I also have a fan running continuously to assist circulation.
I have never had any problems with my orchids.
Having said that, given the choice, a vented system has to be better even if much heat does go up the chimney!
Richard

raybark · #5 11-06-2009, 06:15 PM

Quote:

Originally Posted by richardb

Having said that, given the choice, a vented system has to be better even if much heat does go up the chimney!
Richard

And if you want to go even further, get one with a separated combustion chamber.

Last time I bought a new heater, I bought a Reznor with that feature. It looks just like a Modine "Hot Dawg", but the combustion air is brought in from outside, and then the exhaust gases are expelled through another vent pipe that runs inside of the intake pipe.

The result is that the intake air is heated to give greater efficiency, the controls last longer as they never see the humidity of the greenhouse, and the heat and humidity are not drawn out with the exhaust.

Replacing my old Modine with that heater reduced my fuel consumption by 40%.

richardb · #6 11-09-2009, 03:36 PM

That sounds excellent and exactly what we need - rather like a domestic "balanced flue" outlet. I shall have a look around to see if there is such a system available here in England. Using propane cylindars I could really do with a 40% drop in consumption at their prices. I have already had a look at their website, but I guess I shall have to search for a model small enough for 12 X 8 greenhouse.
Richard

suzyqorchids · #7 11-11-2009, 02:24 PM

My heater is a direct vent Empire Model DV25--more than enought heat for my 10x12 attached greenhouse--runs on propane or natural gas and has been very reliable. Sounds like the venting system is similar to Ray's. I did buy a new, more accurate thermostat that what it came with, and it hums right along now. Got it at www.littlegreenhouse.com.