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Workshop Heating

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  • Workshop Heating

    I have a 24x30 garage, that I want to heat so I can use my machines without a coat and gloves. I have tried a torpedo heater, but that just makes the machines wet when it heats up.
    The garage is 8" block, 2 lightly insulated garage doors, soon to be insulated 8ft high flat ceiling. Any suggestions on what size and type of heater to use? I Don't have natural gas available. Any pointers on insulation, or tips from anyone with a similar setup would be appreciated. Also, any tips on keeping the machines from sweating would be helpful.

  • #2
    I've tried using kerosine heater which works well but it stinks up the garage and you have to keep refueling it.

    Last year, I made the plunge to insulate the garage and get two 4800W electric forced air heater. The key to preventing the sweating is to maintain the temperature of the garage around 7-10*C all the time. Fortunately, these electric heaters have built-in thermostat so it's easy to control the temperature.

    Even on the coldest of nights here in Toronto, I can enter the garage and start working. I crank up the heater and in less than 10min it gets toasty warm enough that I'm working in my t-shirt

    I've been told that a linear overhead gas heater (what many commercial garages use) is the most economic and efficient way of heating the garage.



    • #3
      By 8" block I assume you mean concrete block. If so, the first thing to do is isulate the walls. 8" of concrete has a negligible R-factor.
      I'd get some 2" thick extruded polystyrene insulation board and glue it to the inside of the walls, then glue 1/2" sheetrock over it for a fire barrier (required by code). There's a special construction adhesive for foam you can buy in "caulking" tubes that's easy to apply. That's basically what I did in my basement, about 20 years ago, and it's still doing fine. Just doing that will make the place feel warmer, because you won't have those cold walls sucking away all the heat.
      As far as heating it, a propane-fired hot air furnace might be the most economical and hassle-free. You wouldn't need a very big one. That assumes you have propane delivery in your area.
      Another approach might be one of those pellet-burning stoves, although you'd have to keep tending it a couple times a day.
      Electric would be the simplest, but also the most expensive.

      Try to make a living, not a killing. -- Utah Phillips
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      • #4
        I put a hot air funace in my barn last year. Very good idea. Barn is 24X24 two stories. Wood shop upstairs and machine shop downstairs. The furnace does not take up too much room it is aprox. 2' square oil tank is close to overhead door. Used to have a wood fired furnace with blower but that got tiresome after 15 years. Oil furnace is much faster. One need not place it inside, you could build a shed roof outside and just run the heating ducts inside also the cold air return from inside. Now I go out to the barn and flip a switch and in ten minutes it is comfortable enough to begin working.
        A pellet stove would also be good idea as I use one to heat my home, one needs to fill it once a day. In a shop enviroment one could turn it down when not in the shop and just crank it up when you are and mayby fill every other day. Pellet stoves are neat and clean burning and completely free of anoying pests such as ants and spiders. I will soon be buying another to keep in the cellar.

        Paul G.
        Paul G.


        • #5
          Wood magazine did an article on that a couple months ago for woodworking shops, but it should also suit your needs. Your local library may have a copy of the issue, I can't find my issue but believe it was in August. They tested all the different types of systems and gave plus/minus for each type.



          • #6
            mnadeja: if you have an open flame in your shop you will probably have a dampness problem. Electrical heat is "dry". A furnace where the products of combustion are vented to out side is dry. but if the flame heats the air induse the room you will have high humidity unless the place is well ventilated and that is expensive.


            • #7
              I have a 24 x 30 shop frame construction.I insulated the garage doors with 1 in thick blue foam board.The attic has 12 in of blown in cellulose insulation & walls filled with fiberglass .I'm heating it with a ceiling mounted propane furnace with an 80% heating efficiency(90 gal.tank outside) & it does a great job of heating.I keep the thermostat set at 45 degrees when I'm not in the shop for the evening & around 60 when I'm working& haven't had any problems with sweating.My sweating problems come in the spring when it's warm outside & the garage is cool & I open up the doors.It takes approx. 30 min to get to 60 degrees from 45 degrees, but you can still feel cold radiating off of equipment for a few hours.The down side propane is expensive(in my opinion),I spend about $350.over the winter months to keep the place heated.A friend of mine heats his with a downdraft oil furnace.The floors & shop are always toasty.He claims he gets by with 1 tank (275 gal $?) a season.I believe if i had to do it over again I would go with the oil downdraft instead of propane.


              [This message has been edited by burnlast (edited 10-18-2002).]
              ...the order of bringing about change
              is the four boxes:


              • #8
                My shop is 28 by 36, 10 foot ceiling with 2 overhead doors. With r-20 insulation in the walls and R-40 in the ceiling the heat loss is right around 50,000 BTU/hr at a 105 degree temperature differential. That makes it about 65 inside when it's -40 outside. I don't think it gets anywhere near that cold where you are so a 30 to 40,000 BTU heater should do you fine if you insulate well. If your interested I think I can round up an Excel spreadsheet that I put together to do heat loss on my shop. It's not necessarily user friendly but we can muddle through it. You'd be amazed at how much difference a little insulation can make in cutting down heat loss.

                I put an overhead radiant heater in my shop. It's pretty efficient and the heat can't be beat. Almost like a woodstove where the radiant heat warms you to the bone. Mines natural gas but I think you can get them set up for propane. Propanes expensive but the radiant heater is nice heat.


                • #9
                  Check out the waste oil heater topic on this forum from a few days ago. I have expanded the info on the waste oil heater plans.


                  • #10
                    I have a 24 x 40 2 full story shop/garage as of now I keep the 2nd story closed off mainly use for storage. I have a 45000 BTU hanging gas heater with a low temp thermostat goes down to 40 where standard house only goes to 60..ish. I wanted to put in a larger furnace but my furnace guy told me a larger one would be cycling on and off too much to heat up and would rust out before its time.
                    In winter I keep the stairway closed off with a insulating sheet ,only heat the lower level keep thermostat at 40 when not in use only takes short time to warm up. Garage is well insulated and sheetrocked. This is in tropical southern Minnesota . A thing to keep in mind my insurance company would not insure garage if I would have used wood heat check with your company
                    there is a fine line
                    between \"hobby\" and
                    mental illness


                    • #11
                      We use coal heat in our shop 30'x40' . Fast and hot! when it's 20 below out side we only go through about 2 wheel barrels. The only draw back is if you don't have coal in your area. Shipping will cost more then the coal!


                      • #12
                        If you have a slab floor the most efficient way to heat would be with overhead radiant infrared heaters. One company making them is Reverberay. You may be able to convert them to run on propane. They are quiet and have no moving parts. They work by heating the slab with radiated heat which then in turn heats the air and other objects. With blowers you are heating the air, which will stratify, leaving uneven temperatures and causing longer run time and increased fuel use. It would be best if you can run a natural gas line out to your shop.

                        Radiant infrared is used on loading docks and similar semi open spaces where no other type of heater will work, and they do a very good job of keeping these spaces comfortable.

                        You also should definately insulate and seal off drafts. Whatever insulation you use, should be noncombustable or fireproofed.

                        If you use any type of combustion heating, make sure you have adequite air intake for combustion and proper venting of flue gases.

                        Electric heating is clean and silent, but costs more.

                        If you need more info about heating email me.
                        [email protected]


                        • #13
                          I heat my shop which incidently I work in full time with a wood burner.
                          This one is a little different though. It's designed to burn sawdust.
                          When I was looking for a stove I looked at many so called sawdust stoves but found that non of them would burn pure sawdust.
                          You had to mix it wth wood often 50/50 to get them to burn.
                          I then came across the design for the one I have now. I'll readily admit I didn't design it, it was designed by a friend of mine.
                          I live in a place called Long Eaton near Nottingham in the UK [ Robin Hood country ]
                          For some explicable reason we live in a place that is unique to one trade. This is chair frame making. Around this area are many small manufacturers who make the wooden frames for settee's and chairs. Without exagerating they run into the 100's.
                          Nowhere else in the UK does this happen and one one can explain it. Many of these firms are my customers as I do a lot of machinery repairs. As they always use beech for the frames and the shavings and sawdaust is always mixed as it goes thru the dust units the waste has no value. Animal breeders and farms don't want it as it contains very sharp splinters so this stuff has to be paid to be dumped.
                          I collect the full bags of sawdust and shaving in the large wheelie bin sized plastic bags. The stove holds one bag and it burns for 4 hours on one charge giving off great ammounts of heat.
                          It's unique in that it contains no moving parts and it burns fron the top down. The base is solid steel and it has no grate at all. Air is drawn into the fire thru 4 side louvre plates and as it burns it heats the dust up below it and this obviously produces a gas that circulates thru the louver plates.
                          Quite hard to explain but if you look inside when it's burning you can see the recirculation taking place. This causes a draught and so accelerates the process. When it's burning evenly it has a low roar.
                          I have to go away tomorrow for 4 days so I can't do much about this but is anyone want's sketches or pics I'll be glad to share when I get back.

                          John S.

                          Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


                          • #14
                            A tip for you pellet stove burners. Perhaps some ofyou already do this. Take a 3 pound coffee can and fill it to the bottom ring with pellets. Pour in one bottle of gas line antifreeze. The cheap stuff is fine. Let it sit about 24 hours and it will swell the pellets to almost fill the can. It keeps well in the covered can and lights with a match. Just place a small handful on top of the pellets you want to start. I also use it to light the wood stove when I am to lazy to make kindling. Mike


                            • #15
                              For years I tried to heat my shop with a big King wood stove. Got too old to hustle firewood and for sure too poor to pay someone to cut it and haul it to me. Last year, I went to Lowes and bought a wall mounted propane heater and installed it and leased a propane tank. Since shop is in basement of house, said heater heated up both floors very nicely. Machines stayed warm and dry and so did I!!