Propane Heater

[Peter Stahl]

Want to get a propane heater for the garage to take the chill off for Christmas Eve as this is the smokers hang out. Also a place to get away from the screaming kids too. Will the heater in the picture below heat up a 2 car garage? The garage has about a 10 foot ceiling, it is attached with one window and is fully sheet rocked, no insulattion. Seem to be pretty tight as far as drafts go. I'm guessing that the temp outside will 30 - 35 deg that night. We don't normally get much colder than that (without wind chill factor) this time of year. Not looking to make it t-shirt warm in there. Would like to get about 55 - 60 deg. Will probaly use it when I do a oil change or something like that, shop is in the basement. Thanks for any replies.

Pete

[John Miliunas]

Peter, that largely depends on if the garage is insulated and generally how tight it is. I had the smaller version of that I used in my old WW shop, but only after I did an initial warmup with a torpedo forced air unit. It wasn't the best insulated room but, there was some and it maintained a reasonably comfortable temp in there. Does your garage have a ceiling or open rafters? That will make a big difference, as well.:) :cool:

[Peter Stahl]

John, thanks for the reply. I'll edit my initial post to give more details.

[Jim Dunn]

Pete as I smoke too I know what you mean. Give em a drink as they go out the door and it'll be warm enough:)

[Frank Hagan]

Peter, it will probably work OK in your area ... the usual formula for a regular house is to estimate your Btu requirements by taking the square feet of floor area to be heated times 28 in areas where it gets very cold. (A 20 x 20 ft. room = 400 sq. ft. x 28 or 11,200 Btu/hr.) That's the formula for Nebraskan winters that I just looked up today, and I would expect South Jersey to be about the same (or even milder). Your garage may have many more air leaks than a house, so you may need more than that BTU rating per hour to keep it warm. The heater should have the BTU output on the label or carton.

Make sure it has an "ODS" sensor ... "Oxygen Depletion Sensor" ... for safety's sake. It will shut off the heater if the oxygen level gets too low due to CO2 and carbon monoxide. All of them are supposed to have them now.

If your garage is well sealed, you will want to make some provision for fresh air. Most garages are "loose" enough that its not a problem for that kind of unit, and often you can even seal up some of the air vents to help with the heating! If you have screened ventilation vents along the floor of the garage, measure the opening size and deduct 50% for the screening or louvers. You only need 1" of net vent area per 4,000 BTU/hr of your heater, so that's only 5" square inches for a heater with 20,000 BTU/hr output. You can seal up all but that 5" square inches. You need that along the floor, and then another 5" square inches along the cieling. You aren't supposed to really count cracks less than 1/2" wide, but often you have enough air circulation through a loose fitting garage door to provide the ventilation air at the top of the room.

One problem you may have is that all gas operated appliances give off a lot of water vapor in the flue gasses. When propane burns it gives off CO2, CO (carbon monoxide ... bad stuff that kills you), and H2O (water). The heater you have pictured throws off that water vapor into the air in the room since it doesn't have a vent pipe. That water vapor will condense into moisture as the air moves away from the heater and cools, so protect any cast iron surfaces around it. With enough ventilation air this problem goes away. But it can be an issue with cast iron on table saws, band saws, etc.

[John Miliunas]

I think the unit you're looking at is capable of @30K BTU. Personally, I think you'll be fine. Frank brings up several good points regarding the carbon monoxide and moisture output. Just cracking open the window a bit, should make the CO issue non-relavant. What I used to do in my shop is, a little ways behind and above the heater, I had one of those little clamp fans clipped on to a shelf and, once the heater was started, I'd turn it "on". It helped circulate the warm air, as well as provided enough air movement to make the moisture thing a non-issue, as well. I think you'll be fine. There is a bit of an odor with the thing, so you may have to "adjust" the opening of the window accordingly but, use a little common sense and you'll be OK.:) :cool:

[Dennis Peacock]

That heater should work ok.

[Kent Parker]

Pete,

I have a similar sized one in my two un-insulated car shop. It works OK. Doesn't do the whole shop, maybe half of it. Most of the heat goes upwards. If you mounted a fan to blow some of the heat back down that would help. REALLY nice near the heater. IT's HOT!! As mentioned before, make sure you have an air supply. Crack a window or something or get a C02 detector. Mine has a thermo-coupler so if the flame goes out it cools and turns off the gas.
Have a spare tank around.These things suck gas so fast you'll see the condensation on the tank. Great way to know the gas level.

Cheers,

Kent

[Fred Voorhees]

Pete, I use the same propane tank unit, only it has three of the burners and I use it up in my woodshop. The shop is approximately eighteen feet wide by thirty eight feet long with five foot kneewalls and a cieling that is up around twelve feet high. That three burner unit heats up the shop space quite well and in fact, once heated up, I need to cut it off and only turn it on every hour and a half or so, depending on the chill outside. I would think the two burner unit would serve your intended purpose well.

[Frank Hagan]

I found the stat for the amount of moisture LP puts into the air ... its 1.5 gallons per 100,000 btu/hr; and there's about 91,000 btu/hr in a gallon of LP. That's a lot of water vapor, so a bit of ventilation is a good idea.

(I figure at least people will try and protect their cast iron even if they don't care about their health!)

[Carl Eyman]

I have a single unit. It is great if I'm doing bench work like sanding, carving, or assembling small work. Keeps you very comfortable, but it doesn't warm up the whole shop much. It is a lot better than nothing, though.

[Peter Stahl]

Thanks for all the replys. All I need is comfortable, don't want the smoker to stay out there too long. As far as cast iron goes, all that's in the basement. Using my garage as a garage. Now all I need a heater and a full tank of gas. Really appreciate all your comments and concerns and I'll keep the window cracked. Should help get some of the smoke out too.