Heat a 12x20 shop with wood?

[Charles Lent]

You should also read Dave Richards post "Hot In The Shop". He had a thermostat failure in his electric heater.

My shop is heated and cooled with a window style heat pump mounted through the wall, but I live in NC and not the Great White North. I went with the heat pump because it seemed to be the most fire safe choice for heating and cooling. If I lived farther North I would likely have chosen something else.

Charley

[Jim Becker]

More and more, heat pump technology, especially of the MiniSpilt type, is getting more adept at dealing with colder temps. Mine has a pretty good number around that...something like 5ºF. Yes, not as efficient, but for a shop, likely workable. But this type of unit is relatively expensive for a small shop situation; the unit can be had for reasonable cost, especially a small one, but even with a "mostly" self install, HVAC expertise and gear is required to get it up and running finally.

[Charles Lent]

Jim, I agree.

Mini Splits are great, except for the fact that they don't have adequate filters for keeping the saw dust out of them. I'm using a 12 X 20 X 1" pleated furnace filter in my window style heat pump, and I need to replace it about every month because of how well it filters the shop air. Without a good filter, the fins of the heating/cooling coil in a heat pump will quickly plug up and require a difficult cleaning exercise. The same would hold true if the saw dust got into a mini split.

I went with the heat pump to avoid having flame source heating in my shop for fire safety reasons, and my unit doubles as the shop air filtration system. In Northern locations a heat pump isn't usually the best choice because at outside temps below about 35 deg. they loose significant efficiency. If your location rarely sees below freezing temps, a heat pump is a great choice for shop heating and cooling. For colder areas, some other form of back-up heating will need to be added. Many heat pumps contain electric resistance heating elements
to provide this back-up heat source. In the Northern areas a different source of heat will be necessary, although a heat pump will still be a good choice for cooling and heating at times when the outside air temps are above freezing.

Charley

[Jim Becker]

Charles, I've been remarkably impressed that the filters on my MiniSpit, which sits directly behind my CNC, are staying relatively clean. Yes, I use good dust collection, etc, but unlike the previous window AC that was in that space (prior to the CNC), there's very little build-up over time and what little there is is very manageable with just a few minutes of maintenance from time to time.

[Paul Lawrence]

...my unit doubles as the shop air filtration system....

Whoa! (Or Wow!)

[Brian W Evans]

+1 on the Fahrenheat. I have a 5K unit that warms an oversize 3 car garage (800 sq ft +/-) moderately well. The garage is well insulated, however.

I will say that it ain't cheap to run when it's cold. Definitely insulate as much as you can. This will help in the summer as well.

[Tom Dixon]

My take on electric overhead heaters is they are expensive to operate and a fire hazard from fine sawdust in the air.

If you have natural gas I'd strongly recommend considering a closed combustion overhead natural gas, (or propane), heater like the Hot Dawg HDS. I have the 75K BTU unit in my 24x36 shop and it is awesome. For your size shop the 30K BTU unit would do fine. https://www.qcsupply.com/modine-hot-...model-hds.html I recommend getting the Vertical Concentric Vent Kit https://www.qcsupply.com/modine-vert...-vent-kit.html and if you don't want to fiddle with assembling rods and angle iron to mount it there is a flush mount swivel system bracket https://www.qcsupply.com/quicksling-...h-bracket.html. My shop stays toasty and costs very little to keep warm. The initial investment is more but the enclosed combustion is safer and gas is way cheaper than electricity for generating heat.

[Brian W Evans]

If you have natural gas I'd strongly recommend considering a closed combustion overhead natural gas, (or propane), heater like the Hot Dawg HDS.

I actually have one of these in my shopping cart at the same place, for the same reasons you cite. Do you have a thermostat on yours? If so, do you mind sharing which one and how it's hooked up?

Thanks.

[Tom Dixon]

Do you have a thermostat on yours? If so, do you mind sharing which one and how it's hooked up?

Thanks.

Mine was originally hooked to a cheapie provided by the HVAC installer my contractor used when I built the shop. It was installed under and behind the Hot Dawg which is the opposite corner from the entrance double doors. I changed that out to a big box acquired programmable digital thermostat. I don't remember the brand, maybe Honeywell. It will do heat and AC so if I ever install a mini-split AC I'm all set. The key is the programmability. In the winter I have it bring the temp up from 60 at night to 64 on weekdays and to 68 on Saturdays and Sundays so it is comfy to work in. I have another Thermometer/Humidity device on the opposite side from the thermostat and it indicates the thermostat is dead accurate even across the room. I also have a dehumidifier too to help prevent rust on my cast iron. My target is between 40% and 50%

[Tom Bender]

Sounds like you have bought a toolshed and placed it on a concrete slab. It's a start.

If you have gas available it will cost less to heat than electric.

Can you lift it up and insulate the floor from the bottom then set it back down?

Any kind of forced air heating will require some kind of filtering of the return air to keep the heat exchanger clean.

Foam insulation is effective and easy except that it normally requires drywall or something like that to protect it from flame, which would make toxic fumes. Foil faced fiberglass boards are good but more costly.

You may want frame and to install a few good windows.

If you have a sliding door, you will never make it satisfactory. Just seal it shut permanently and install a 36" pedestrian door. Anything too big for that is too big for your shop anyways.

Congrats on the new shop and enjoy it.