Garage Heater

[Matt Wilson]

I want to buy a heater for my garage (shop). The biggest one I can find for a price I can afford is advertised to put out 19,000 BTU's. It is a 240V unit that has a NEMA 6-30P plug. I have an outlet I installed in my garage to accomodate a 240V 50A welder. The outlet (receptacle) is a NEMA 6-50R.

Is it safe for me to make an adapter to go between the 6-30P plug of the heater and the 6-50R receptacle? From the standpoint of current draw, I know the 50A circuit will be safe. It is obviously rated for much higher capacity than what the heater will require. However, I know very little about the different 240V circuit types, so I don't know if there may be incompatibilities that may exist in other ways (ground vs. neutral, 2 hots vs.?, etc).

Any suggestions or advice are appreciated.

Also, I'd like to bounce the idea of this heater off you guys. Putting out 19K BTU's, do you expect that will be satisfactory to keep the garage reasonably warm in winter? My garage is about 24' x 24', 9 feet tall, with 2 of the 4 walls insulated, and garage door is insulated as best as it can be, ceiling is not insulated (not yet, maybe someday). Concrete floor. Comfortable temp for me would be 60 degrees. Outside temps here do not often go below 20 degrees. Do you think this heater will be adequate?


Many thanks.....

[Desoto61]

While I can't see any issue with converting the plug type for your heater, but I think it would be money well spent to finish insulating the garage, especially the ceiling.

I have a 20x30 with 13 ft. ceilings and it's insulated very well and I can heat the garage with a pair of small room heaters, though some of that would depend on how cold it gets where you are.

[Matt Wilson]

Yep, good point. Maybe I need to push the priority up a few notches on the insulation. Would be a good winter project this year.

Thanks,

Matt

[Ron in Indiana]

Matt do you have a ceiling in your garage? If not I'd put one up and add the insulation. This will make a huge difference in comfort and heating. I've found using Owens Corning Attic Cat insulation easy and effective. Home Depot should carry this in your area. Be sure to add eave baffles and batt insulation to move air through the attic by way of eave vents. We've done several retro fits of this insulation and it's an easy DIY job. Batt the remaining walls and go to work in comfort. Come summer the insulation will keep the heat from cooking down on you too.

[Gordon Maney]

You would be astounded at the effect of adding insulation to the ceiling even if you don't heat it. It makes a big difference in summer, too.

Put in at least 6 inches, and go to 12 inches if you can at all afford it.

[MoparNorm]

I agree, insulation is the most cost effective thing you can add to a building.

[Matt Wilson]

Thanks, guys. I think attic insulation will move to the top of the list for the winter.

I do have a ceiling in the garage, just not insulated. In fact, the whole garage is finished out with sheet rock and even textured (done at some point before we moved into the house).

I added insulation to the garage door, and I could tell the difference. Two of the walls adjoin the house and are insulated, but the third is an outside wall and is not insulated. I could drill holes at the top of the sheet rock of that uninsulated wall, between the studs, and blow insulation in there and I'm sure that would make a substantial difference, too. I know blown insulation is not as good as batt, since it compresses over time, but I think that's far better than tearing out the sheet rock to put in batts. However, I am open to other ideas.

I still would like to know about the electrical question. I may still want to get the heater, although I may wait to see how the insulation thing works out.

Thanks again.....

[Matt Wilson]

Nice setup, Norm!

[Ron in Indiana]

The Attic Cat is chopped fiber glass and can be blown into the walls as well. It's not supposed to settle like cellulose and doesn't raise a dust. It's not the itchy fiber glass type either so it's easy to use. It's like cotton candy. Like I said be sure the eaves are open to get the fresh air in the attic space. I'm not an electrician so I'm no help on that part of your post.

[Matt Wilson]

Thanks, Ron. I will look for the Attic Cat.

[Matt Wilson]

Another question, but related:

I can easily put in 6" of insulation, or even a bit more, because the ceiling joists are 2 x 6's (so actually 5.5"). However, I've always wondered about putting in insulation above the joists. Gordon recommended putting in as much as 12", but then I wonder how big a deal it would be to navigate (i.e., walk or crawl) around up there if I have to get up there for any reason. I would be able to see where the joists are located because I would know that they are between the rolls of insulation, but I wouldn't actually be able to SEE the joists, and I wonder how much additional danger there would be in trying to step from one to the next. I've seen houses with very thick blown insulation, and I could not see the joists, but I also did not try to walk around up there either.

Any thoughts on this? If it works out well, I may eventually try to do this with the rest of the house, little by little, as the existing insulation has seen better days.

Thanks again.....

[Gordon Maney]

Another question, but related:

I can easily put in 6" of insulation, or even a bit more, because the ceiling joists are 2 x 6's (so actually 5.5"). However, I've always wondered about putting in insulation above the joists. Gordon recommended putting in as much as 12", but then I wonder how big a deal it would be to navigate (i.e., walk or crawl) around up there if I have to get up there for any reason. I would be able to see where the joists are located because I would know that they are between the rolls of insulation, but I wouldn't actually be able to SEE the joists, and I wonder how much additional danger there would be in trying to step from one to the next. I've seen houses with very thick blown insulation, and I could not see the joists, but I also did not try to walk around up there either.

Any thoughts on this? If it works out well, I may eventually try to do this with the rest of the house, little by little, as the existing insulation has seen better days.

Thanks again.....

I have that very situation in my house, except I don't believe the joists are even 2x6's. Yes, navigating is a problem. You have to pick your way, and then close your tracks as you come back out. Something I have considered and never yet done is to build some sort of elevated catwalk -- even if narrow -- to cover some main paths from one end to the other.

My shop has the same problem as well. Twelve inches of fiberglass and 2x4 joists. As far as blowing it in, you could go up there and make felt tip pen marks 12 inches up on the trusses. Then when you blow it in, all you have to do is make sure all of your marks are covered up. That is a good way to do it if you are hiring someone. It keeps them honest.

[Gordon Maney]

I agree, insulation is the most cost effective thing you can add to a building.

Norm, what are the lights, how long do they take to come on, and what would they be like with low temperatures [like you don't get there] ?

[Ron in Indiana]

Matt how many times do you think you'll be in the attic. Unless you have over a 5/12 pitch I doubt you have much headroom anyways. If you think you need to get up there do as Gordon suggests and build a catwalk. Put 2x6's on edge on top of your joists and lay a 1x10 or 12 on top of that. A 2x 8 or 10 would be better but with the ceiling already in either way it'll hard to get any length up there I would guess. Attic Cat has simple rulers you can staple on your joists so you can better judge the thickness. I don't think you need 12" in your area but they will have the R value per inch of insulation. You can go to Owens Corning's website to see how much you'll need. The insulation is about $28 a bag here. We did 6-8" over 1400 sq ft for $320 for the insulation. Attics are not the best storage spaces.

[MoparNorm]

Norm, what are the lights, how long do they take to come on, and what would they be like with low temperatures [like you don't get there] ?

Metal Halide, they take about 3-4 minutes and I selected them based upon the K degrees for a more natural white light, not yellow.
These are designed for hi-bays at 20' +, the ceiling is only 18 and they rock!

They still work fine, after 8 years, still the original lamps, and it once got all the way down to 65 degrees here... ;)
Actually they have seen a few mornings in the 20's but they are inside the insulated barrier so maybe only was down to 30 degrees inside. Once the infrared heaters kick in, it's toasty warm.