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  • Heating a garage.

    I want to heat my garage. It's brick, it's detatched and it's approximately 21X21. I've looked at kerosene heaters and propane heaters. I have also checked out some hanging radiant heaters. Does anybody have any suggestions for me?

  • #2
    How well insulated is your garage? Do you have natural gas or propane available? My garage is super-insulated, 24 x 32 and I have a 60,000 btu Hot Dawg ceiling mounted propane heater. It's thermostatically controlled . I turn it down to 45 when I'm not using it and up to 60 when I'm in the shop. It works great.
    I'm in Niagara county NY so our weather is comparable. COLD ! ! Just my 2 cents.

    PS I used a kerosene torpedo heater in my old garage. It's loud, dirty and it stinks!

    Edit: If I remember right, the Hot Dawg requires a 10 ft ceiling height. You can check them out at their website.

    [ 02-15-2004, 01:55 PM: Message edited by: Lorax ]
    "Did you put the yellow key in the switch?" TOD 01/09/06


    • #3
      My garage is not insulated at all. I've thought about firing out the walls or throwing insulation on top of the brick. However, I like the look of the brick. I will check out the web site. Thanks.


      • #4
        Reader: I have a 28 x 24 garage/shop that I use an electric heater in. Main reason I have electric is I didn't pipe gas to the garage.

        The heater I use is a Marley Model 562A. It's thermostaticly controled, 220 volts, 5600 watts, 19, 110 btu. Does a great job of heating with it barely turned on. Will easily keep the garage about 55 degrees with the thermostat turned up about 1/4 capacity. Also has fan that comes on when heater kicks in.

        No mater what type of heater you get, I would highly advise to insulate. I have R-13 in the walls and ceiling. Actually, I think I apprecate the insulation as much in the summer as in the winter so it doesn't get so hot in the garage.

        I got my heater from Grainger for right at $100.00. I just ordered another for my father-in-law and they were discontinuing them so the price was $88.00. He also really likes it for his shop.

        If your wanting electric, I would highly reccomend this one. That's my two cents worth.



        • #5
          My shop is 25 x 11 in my attached garage. The ceiling is insulated because the living room is above it. The wall common with the house is insulated. I put a new garage door in, R13 insulation value and I insulated the concrete floor with 2" R10 styrofoam. The other two walls are 8" thick solid concrete. I just installed a Reznor
          30,000 BTU Natural Gas Unit heater and it works great. It vents directly out the wall. Its controlled by a thermostat but I keep it fairly cold when I'm not in there. Only takes about 10 minutes to heat it up to comfortable working temperature.


          • #6
            Key factors, some as stated above. Insulation. Air tight. Eliminate single pain windows. I disagree with turning the heat down low when your not in the shop. You not only have to heat the air, but the objects in the shop, and the interior sheeting of the walls. I turned the heat off for a week in my shop. It only got down to 38 (MI, zero nights, 20 high). Took a full 100lb tank of propane running 36 hours on high to have an active (air, items within, and walls/ceiling) maintained to resume work to 75 degrees. Meaning, if I shut the heat off, there where no cold items in the shop robing the heat from the air, and it maintained temperature and the items within helped keep the air temperature. Maintaining 72 to 75 degrees, 100lb propane tank will last 10 days in the same (zero nights, 20 highs)temperature. My shop is a 24 x 24 pole structure. R10 walls, R20 ceiling. 3/8" plywood ceiling, 1/2" walls. No windows, 2 insulated steel entry doors, 1 9x7 overhead, insulated...if you can call it that. Floor is R9, vapor barrier over dirt, wood floor. No cold immiting concrete (can be a heating nightmare).

            Conclusion: Is your shop brick? or block? Big difference. My suggestion is put up ferring strips, use 1.5" PolyISO between the ferring strips, sheet with 7/16 or 1/2 inch OSB or Plywood. Same for the ceiling, if not double (insulation only). If you have a concrete floor, Lay a grid of 2x4's (treated) on top of a vapor barrier over the concrete, insulate with same, 1.5" ISO. Sub floor of treated 1/2 or 3/4" plywood. Top layer of T&G OSB or Plywood 3/4". T&G (on the floor) keeps direct cold air movement and radiant cold from the concrete below. Any windows can be covered over for the winter with same 1.5" ISO over vapor barrier (3 mill Min. Vesqueen) to stop outside air penitration.

            Block is better than brick, you have the dead air space (natural insulator). Brick is solid and will radiate outside temperatures to the inside. Wind will increase the cold "drive". If your walls are truely brick, use a 1/2 shim on the ferring strips, and the insulation. Create the "dead air space" between the brick and insulation. The best divider between the cold outside and the warm inside is dead air space. Heat the insulations, not the shell of the building.

            Other factors: when fast heating from 50 or below to 70 or above, the cast iron will gain rapid condinsation. (Rust). Also, if your like me, and luch be with you to have 2 hours a night in the shop, I'd rather be working than wiping condinsation off the cast iron. Or spending sundays removing rust and treating the machines in rust prevention.

            Ventless heaters cause high moisture content in the air if a constant temperature is not maintained. Zero heat loss. Vented heaters have a much lower air moisture content, better for drying wood, a little more costly to operate. Also, ventless heaters (depending upon your local codes) can be illegal, cause insurance denials and generally bad for your health if fresh air isn't introduced regularly. Mine is ventless, and let in fresh air each time into the shop. I have no insurance, and my health already is 6' under. For me, it's a cost factor. Not recommended for everyone.
            John E. Adams<br /><a href=\"\" target=\"_blank\"></a>


            • #7
              The garage is brick not block. Unfortunately I also use the garage for two cars so I can't do anything about the floor. The ceiling is about 10' . There is a loft space above the ceiling so I can insulate there. I've been checking out the Grainger web site to get an idea of what's available.


              • #8
                I've got a 70,000 - 210,000 BTU propane heater purchased from HD for $120. Wish I'd known that it is way overkill when I bought it. It's basically a sheet metal cylinder (verticle) with a giant burner in the bottom. Sounds like a jet engine at full roar.

                If you are interested, let me know and I'll get the name of the manufacturer - they're local to me.


                • #9
                  If you have the room and the wood supply you might consider a wood burner. I looked at all the options and choose to go with a cast iron stove. Set it out of the way with a small fan behind it and it works great. On a really cold evening it takes about 45 to 60 minutes to heat the garage up to shrit sleeve temp. Just enough time to eat supper.
                  I came...<br /><br />I saw...<br /><br />I changed the plans.


                  • #10
                    I use a kerosene to heat my garage. This works okay because I'm not in it everynight. I live in Nashville, Tn so it has to get pretty cold outside for my garage temp to drop below 40 degrees. I turn the heater on an hour or so before I plan to use it and usually the temp is okay for work. Whether I keep the heater on or off depends on what work I plan to do. If I'm doing hand work, I'll usually keep it on low if the outside temp is low. If I'm using a piece of power machinery I'll turn it off. I don't assemble (glue) or finish until the temp is right.
                    Next winter I may buy one of two quartz radiant heaters from Lee Valley. This look nice and you have a lighting option. Go to and do an item search on item number 27k08.10. I can get 2 of these for about what I paid for my kerosene heater and they're safer, less costly to operate, don't take up space, and offer the lighting option.


                    • #11
                      Originally posted by Jeff P:
                      My shop is 25 x 11 in my attached garage. The ceiling is insulated because the living room is above it. The wall common with the house is insulated. I put a new garage door in, R13 insulation value and I insulated the concrete floor with 2" R10 styrofoam. The other two walls are 8" thick solid concrete. I just installed a Reznor
                      30,000 BTU Natural Gas Unit heater and it works great. It vents directly out the wall. Its controlled by a thermostat but I keep it fairly cold when I'm not in there. Only takes about 10 minutes to heat it up to comfortable working temperature.
                      Use similar one, but larger sized. Wonderful unit.Larger shop s/f also.

                      Woody - while you are mainly correct in not turning down the temp we Northern Ducks have no choice. It's easy to blow 300-400/mo in natural gas and I have very insulated shop(s) but higher ceilings and doors get opened often. But our winter air is extremely dry too - never yet had condensation. Doubt even possible - everyone runs humidifers!

                      Since I swapped units and now keep temp at 36-40 range at night I find heating bill dropped dramatically. $180 last month and coldest in many years. Very pleased - expected $400 and above.

                      Reznor makes real good and efficient units. Need to deal with other shop next and swap out too. That is electric heat and solid $300 month and smaller too. Better insulated even - it's just these stinking winters - they real expensive. But no a/c needed in summer either
                      Have a great weekend all
                      Wish I had the answers ..... even half of \'em


                      • #12
                        I have a detached garage 20' x 30', ceiling is 11' high. Walls are well insulated. However; the ceiling is not insulated, the insulation is installed on the interior side of the roof between the 2x4's?
                        The ceiling has wafer board layed out for storage space exposing the 2x4's from the garage side, there is an opening in the middle from front to back (of garage) for access.
                        I have a natural gas heater (non-vented). My problem is condensation between the insulation and the roof. When I have the heater on that's when it's a problem. It's running down the walls stained with I'm assuming rust from the roofing nails. I have a electric vent w/thermostat installed on the roof that works great during summer, but don't use it now or I'll be losing heat and wasting gas.
                        My only solution at this point is to finish the ceiling with insulation and install two gable vents in the "attic" to ventilate.
                        Any other suggestions would be appreciated. I live in Utah if it helps. I bought this home in May 03 as is.


                        • #13
                          When cold air hits warm air you get condensation.
                          To do this right you would need to take the insulation off the roof and put R20 in the ceiling with a vapour barrier, make sure the insulation does not totally block the soffit vents and you have adaquate roff vents or a ridge vent. Only problem is that you loose the heated storage area.
                          You may be able to put a vapour barrier over the existing insulation but to get a continuous seal would be near impossible with all the roof supports to work around and you would have to seal all the soffit vents. This can also create problems if the roof is shingled as there will be no where for the heat to dissapate during the summer and you shinge life will be shortened drasticly.
                          If you really want the space and dont care about the shingles cause you wanted a metal roof anyway you could use expanding foam. No not the wee cans of it. It comes in large containers meant for doing insulation or you could hire out the job.
                          Here is a link to the foam kits


                          • #14
                            I'd leave the insulation on the 2x4s below the deck. You'll need to seal off the area that is open to above and put some type of ladder in there. Then insulate your shop space ceiling.

                            The problem is occurring because there isn't enough circulation between the cold space above and the warm air in the shop. Also, it sounds like the roof isn't insulated too well either. Also check the insulation to see if it is wet. Wet insulation does not insulate and will cause what you describe. (could be wet because of leak in roof, but now it transfers cold air to the inside of the shop)


                            • #15
                              The insulation on the roof is the wrapped type (no F/G exposed) and its in there pretty tight. So, sounds like I should set it up like a typical home with attic? Seperate the two areas and pull off the old insulation from the roof and maybe install two gable vents to breath.