Shop heat: what about Volume?

[Dan Bundy]

I've seen a lot of threads about heating a shop that talk about the square footage, but how much of an issue is volume? My shop is my two-car garage (a little bigger than 20' x 20'), so not a lot of square feet, but it's ceiling is 16 or 18 feet up, so with heat rising, it seems to me like it would take a lot of heat to finally make it's way down to the working area.

The rear wall (opposite the big door) is shared by the house, so it's insulated and I've insulate the door with an insulating kit. About half of one side wall is also shared by living space, so insulated. Don't know about the other side wall but given how cold it gets out there, I'm guessing no insulation and there is currently no insulation over the ceiling, but it's on the to-do list.

I'm not looking to make it super-warm, but if it could get up to the mid-50s or so on a 20-degree day, that would be great. Any suggestions, advice, caveats?

Thanks. DB

[Andy Giddings]

Depends on which fuel source you want to try, but you could easily order one of Amazon's 5kW electric heaters to trial and, if it doesn't work due to volume of space, return and try something bigger?

[Rollie Kelly]

As you have so much overhead clearance, while you are insulating the ceiling, hang a couple of ceiling fans. When switched to blow up, they will force the warm air out to and down the walls preventing heat stratification. You don't want them blowing down or at a high velocity which will cause a sensible breeze making you feel cooler.

[Jim Becker]

The square foot parameters that accompany many of the heating solutions we use "assume" normal ceiling heights, so you are absolutely correct that you have to take into account the real volume of air that's involved when making a heating plan. Your shop with the "double high" ceilings has twice the volume, so you'll need to go larger with whatever type of heating you choose. But it also could bring advantages in that you can use "high bay" solutions that folks with 8' ceilings cannot use, particularly for radiant units.

[Sam Layton]

My shop is 35' X 50' . The side walls are 12' tall and the inside peak of the ceiling is about 17' tall. I have 3 ceiling fans down the center to blow the heat down in the winter. I keep the shop about 45 deg when I am not in the shop. When working, I turn the heat up to 60 to 65 deg, plus turn the ceiling fans on to circulate the hot air down. I have a natural gas, ceiling mount heater. It does not seem to be a problem keeping the shop heated. In addition, the shop has 6" walls, double pane windows, and the door is 14' X 14', 2" insulated door.

The ceiling fans seem to do a good job. In the summer they also provide circulation as well.

[Pat Barry]

I would take some plastic sheeting and attach it to the joists above and create a false ceiling for the winter. No reason to heat the rafters and all that space up there anyway

[peter gagliardi]

As it was explained to me, by a registered professional heating engineer with a PHd. "heat doesn't rise, hot air does" I find this to be true, because in a radiant floor type situation, it is warmest near the floor- the heat emitting device. The ceiling area in this type will be several degrees colder than the floor area, be it 8' or 18' of separation.
Hot air rises, but heat radiates in all directions equally.
Part of the reason forced hot air is such lousy heat.

[Dan Bundy]

Thanks for the replies. False ceiling is an interesting idea, but it's a finished ceiling with lighting WAAAY up there, so that would probably not work (no exposed rafters, etc. Lighting is dicey as it is; I put a 150w LED flood in the one ceiling fixture and also turn on the door opener light, in addition to so moveable lamps and work lights (lighting is a whole other deal). Pretty much going to have to go with electric as there is no natural gas to the neighborhood unless I want to put a tank in. I've used kerosene in the past in a different shop, but didn't like the fumes.

You've given me some stuff to think about. Thanks again.