Heating a Woodshop
From the original questioner:
Thanks. Do you do any finishing in your shop and if so, what about fumes? Wouldn't think of spraying anything with the heater, but maybe hand applied poly?
I moved to NC from Maryland, and for the most part the winters here are a bit milder (it was downright hot and humid here today), but in the colder months I use an electric heater to take the chill off the shop. I am concerned about sparks. Fire is very bad, and it spreads very rapidly in a woodshop.
A friend uses a woodstove, but he is a turner, and the shavings he produces are usually damp and not particularly dusty. Fine dust hanging in the air can explode with a great deal of force.
Based on my observations, a woodstove that sits outside and heats water which is circulated in the area to be heated is about the best solution. I produce a lot of scrap, and it sure would be nice to heat the shop and house with it.
NY can get real cold. Preparing for protracted cold snaps is the key to surviving and thriving. Ask around at local shops. People who have been there a while are probably your best resource for info.
I use a 100k btu unit heater for my 2000 sq. ft. shop. While in my case this works well, it is not recommended that any open flame heater be used in a dusty environment. The best heat would be radiant hot water heating in floor or baseboard. Another good choice would be sealed combustion chamber direct vent heaters. The unit heater works for me because I keep dust to a minimum with a good central dust collection system and
ceiling mounted air cleaners.
I have a standard oil fired hot air system in my two story, 1200 sq.ft. per floor shop. It works just as well as in any house, with the exception that we have a pre-filter on the cold air return and clean filters every two weeks.
I wish I had installed a hot water baseboard system instead. I think it would have been easier to maintain, requiring only an air dusting of the radiator fins perhaps once a week.
I do finishing in the winter on a limited bases. If there is something I have to do, I get the shop warm and turn the heater off. I will open up the roll up door and spray what I need to. After the fumes have dissipated, I close the door. You should not have to worry about the humidity in the winter. We only have about 12% humidity here in MN most winters and I think upstate NY will be close. I spray lacquer and epoxy. Heck, I just painted my 41 Chevy in the shop with base coat, clear coat, and it came out perfect.
I'm going through the same issue (although not as chilly), except I don't have natural gas available. Has anyone heard of indoor propane heaters (I can vent it through the roof if necessary) or other alternatives? I've got 2400 square feet with16 foot ceilings. I'm hoping to avoid electric.
Almost all gas heaters are available with a propane kit. I run my unit heater on propane. With 16 foot ceilings, the overhead radiant heaters work well. They have closed combustion chambers and come in lengths to fit most buildings. I would have gone with this type if I had higher ceilings. Mine are 10 feet, which is low for this system.
I have a 30x48 shop with 12' ceilings and live in MN. I have a 100k btu natural gas ceiling-mounted Reznor furnace that is maintained at 50 degrees, at least, when I am not in the shop. I usually only turn it up to 60 when I am in there working. This is a very nice heater and it is a direct vent with a separated combustion chamber, so I can use paints and other chemicals without the hazard of explosions.
When the heat is turned down or off, the humidity will increase quite a bit. Then when the heat is turned back on, the RH drops and the wood surface can dry rapidly and develop small cracks (checks). So, a fairly constant heat is best. Also, purchase a $25 RH digital sensor from Radio Shack or similar and monitor your RH, avoiding over 40% RH in the wintertime. The reason we do not want high RH is that a house or office will be 30% RH average in the wintertime, or even lower. So if the shop is humid, the wood in a finished project will dry and shrink when moved into a home or office.
I just purchased an Amish wood heater, which sits about 10' from the outer wall of my shop (2400 sqft). I burn all my waste and sawdust, which so far has been more than adequate to heat my shop with zero fuel cost. The best $2000 I have ever spent.
I've used a propane heater, mounted at the ceiling level, for ten years in a 1200 sq. ft. shop. I do have both dust collection and a collector to filter the ambient air. Works fine for me.
I am currently managing to keep my shop at around 100 degrees every day. Glue sets quickly, and if it rains on the wood pile, the wood dries out quickly. I really like summer a lot.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor H:
Comment from contributor D:
I live in Montana and it does get cold at times. When I built my shop, I plumbed my concrete floor for hot water heat. Three zones. I use propane. The hot water heater was a recyled unit from a local store. My shop is 24 x 36 with 3" sprayed foam insulated walls. In the winter I set my thermostat at 50 and warm the shop to a working temp with a woodstove burning my scraps. Pretty efficient.
Comment from contributor N:
If you're going to build a shop from scratch with a concrete floor, I would wholeheartedly endorse using radiant heat with an outdoor wood boiler. You affix Pex flexible plastic tubing to your remesh grid in an "S" pattern to cover the area and then circulate hot water from the boiler to heat the shop. If it's a big area, you'll want to use two loops, overlapping - one which starts at one end with a hot water inlet and the overlapping loop which is reversed. This prevents one end of the slab from being considerably warmer than the other. You have to insulate the slab and use a thick plastic vapor barrier (6 mil or better), but the end result is a toasty shop with no indoor moving parts or exposed heat exchangers to worry about getting clogged with sawdust. Another plus is that you can have all the hot water you can stand for next to nothing. And it provides a great means of disposing of your wood scraps. If you're building a shop from the ground up, this is the system to consider.
Comment from contributor L:
Be cautious if using a vent-less natural gas heater. I had one in my shop for some time, and most people do not know this, but the natural gas burns a great deal of moisture into the air. It was causing me trouble with projects when brought inside after acclimation. There was lots of shrinkage, even when tested with a moisture meter. I also had moisture collecting in the eaves, which caused a small amount of mold. I recently switched to electric thanks to a friend in the heating and cooling business. A used electric home furnace, which was cut in half, is now hanging from the ceiling of my 16 x 24 shop, set on 60 degrees with a thermostat, and heats awesome. The electric is also a dry heat, so I am guaranteed to get my wood down to the right percentage.
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