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Garage heater advice

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  • Garage heater advice

    Well, after a few weeks of 80 degree weather here in Colorado, the cold decided it was time to make an appearence and we've been locked a freezing drizzle for the past 4 days. Needless to say, the little 1500W electric heater in my garage didn't help too much the past few days. I have a detached, uninsulated garage that is about 8'x24' (although it's not all dedicated as a shop) with open air all the way to the roof- that is to say that I need to heat the entire volume, including the storage up in the rafters. Given that it is a condo garage, I can't add extra power (now that's a whole topic into itself ) or tap into any other source of heat. Basically, I think I need to go with a propane heater if I'm going to be able to work in there successfully. A little background about me- when I'm not hanging out in the garage, I'm outside hiking/biking/skiing/etc even in some of the most adverse conditions known to man. Here's the point: I don't mind being cold while working, but I highly doubt that any project that needs to be assembled with glue or have finish applied will look so kindly on the cold.

    From what I have seen at Home Depot and Lowe's, there are 3 styles of propane heaters: radiative, forced air, and convective, all of which put out enough BTU's to adequately heat my area. Here's what I'm confused about:
    1) Are all of the heaters safe to use inside, or do they require the oxygen depletion sensor with automatic shutoff to be considered indoor rated?
    2) It seems that getting the garage up to a warmer temperature quickly is the main motivation for going with a large BTU heater, which could then be turned off for a while. Any preferences on the type of heater here? Forced air seem like they could warm up the space quickest, convective apparently gives a "cozy" feel, and radiative is by far the cheapest.

  • #2
    Burning x amount of propane to produce heat is going to use oxygen, so the more you seal the garage to keep the heat in, the more problem you will have with carbon monoxide and oxygen depletion. That would be my worry, but that isn't my area of expertise.

    Radiant heat is directional, so you may be baking your projects. Once a surface gets heated by radiant heat, it warms the air around it, and becomes convection, but that is a while later.

    I would worry about getting convective heat into the corners, under the workbench, on the back side of projects, etc., if the garage is heated intermittently.

    My solution in Texas (where we need far less heat) is to use an electric space heater that blows hot air around the garage.


    • #3
      I don't have the TRUE knowledge but here's the idea I've been kickin' around. I saw a little heater gizmo that basically connects to the top of a 20# propane bottle, (which since the grill isn't being used I happen to have already to go) for about $40. Throw in a battery operated CO1 sensor / alarm and heat the space as needed. It seems like a pretty good option for the $$$ but Oxygen depletion sounds like a scary thought, however I've got a roll up door that will NEVER be air tight!


      • #4
        Yeah, I like the thought of the cheap $40 model, but as Charlie pointed out, the idea of using radiative heat in the shop has some down sides. In regards to using a CO sensor, if the heater is working efficiently (which a new one should), the combustion should be converting the fuel and oxygen to heat and CO2, with very little CO as a by-product. So the oxygen will slowly be replaced by CO2, which the CO detector won't notice, which could lead to some bad things (see a pretty neat article on CO2 inhalation in "National Geographic Adventure" magazine, Nov 2003 issue).

        Right now, I'm leaning towards the Reddy Heater tube style, force air heater ($99) that connects to a propane tank. From looking at the box at Lowes, I think it has an oxygen sensor, will crank out heat very fast, and circulate it throughout the shop. Unfortunately, the Reddy Heater website doesn't have current models (last updated 2002), so I haven't found any definite answers on the oxygen sensor.


        • #5
          I, too, would appreciate input on this topic. Since moving to a new house, with a much more substantial garage than before, I now have a dedicated workshop in the 3rd stall of my garage. It is insulated, but does not have a heat source. I want to have adequate heat without suffocation or combustion concerns.


          • #6
            Being in Wisconsin with an oversized 3 stall garage, I have tried many things over the years and will make the following suggestions:
            My garage never maintained warmth until I did something about it rising too quickly. With exposed rafters, nothing short of a high BTU forced air system will work unless you keep it from disappearing so fast. I would recommend some plastic sheeting in the rafters at the minimum. Radiant heaters will never give even heat unless left on constantly across several days. The things facing them get warm, but the stuff facing away or in a drawer stay cold. A 1500w elecric heater can usually maintain heat after you warm things up, so I would go with a propane forced air heater to get up to temp quickly and keep the electric ready after shutoff. If your garage is attached to the house like mine, opening the door to the garage a half hour before heading out is a great way to boost the temp quickly. Now that my garage is insulated, my house can boost the garage temp 20 degrees in that half hour. (you may have to send the wife shopping first though!)
            \"Is it Friday yet?\"


            • #7
              Re: Garage heater advice

              I am not sure about the oxygen depletion or carbon monoxide levels. But, an easy way to determine what you need to keep the chill off while you are in your garage in the winter is to use a garage heater calculator. Then you can buy the exact heater that fits your needs.


              • #8
                Re: Garage heater advice

                I have a small shop 20x24 A couple years ago I bit the bullett and insulated the walls and ceiling. I put in a pull down ladder to access the attic. It was the best money I have ever spent. I take the chill off with a 40,000 BTU forced hot air propane heater, a salamander type. I have an electric heater I use to maintain the temperature. I keep a monitor plugged in constantly. The heating system works OK for me. It is less desirable than a dedicated heat unit but I have dug so many fifty feet trenches from the house to the garage that I am not ready to dig another one to run natural gas out there. Propane furnaces are not allowed in my city without a long permitting process.

                One thing to be aware of is that a byproduct of propane combustion is water vapor. The result of the water vapor in the air and settling on your tools is rust. You will have to maintain constant vigilance to prevent the rust if you heat with a non vented propane heater.

                Last edited by Tom W; 05-19-2008, 11:14 AM.


                • #9
                  Re: Garage heater advice

                  Try a Infra Red Heater. The advantage is that they heat surfaces and people not the air. Here is a link to one


                  • #10
                    Re: Garage heater advice

                    Do it the right way. Another vote for an infrared garage heater such as this. No worries about gassing yourself or your family.


                    • #11
                      Re: Garage heater advice

                      As a previous poster said, get insulated first. Sheets was a good idea. If this is a dedicated shop that you may enlarge at sometime, you may want to look into a mid to high end garage heater. You would need a 240 outlet. has several garage heaters to choose from.

                      On a smaller budget scale, they have a Ouellet portable, 240v 4000 watts. Model och4000. Only 80 bucks.

                      With any garage heater, you need a good fan, so that is something to definitely look for. 2000 watts or higher. Menards has some really decent propane heaters that can be mounted in the wall. Around 200 bucks or so.

                      Just figure your square footage, how much gets out (if you dont insulate), how long you will be in for (do you need fast heat). Take these all into consideration before buying. Something too much and you'll bake yourself, and waste energy costs.