Hi everyone. I've done some investigating on here and didn't see this exact question, but forgive me if this has already been addressed elsewhere…
I have a detached 22' x 18' two-car garage workshop in Chicago. Every night I have to park both our cars in it, so space is really tight. It's so tight in fact that I like having the studs exposed for two walls (the third is a firewall by code so I have to have it covered) so I can use the 3.5" depth that gives me between studs for storage. Yes, it's that tight. I have no ac or heater currently. I have a wall-mounted fan that does an okay job of cooling things a bit in the summer, but that's it. In the winter it gets too cold to work when it gets below 40.
I don't have any tools that require 220v but I'm having my electrical redone and have an opportunity to upgrade (for more $$), and was thinking about an electrical heater (like a NewAir G73 or something). So my question is that if I continue to choose uninsulated walls (for the space saving) am I wasting my time even thinking about heat? I have no space for a stove, but I could hang a radiant over where I wheel my bench out to. It just seems from reading these boards that for a small shop the electric 220v ones are the way to go. Should I even bother if I don't insulate?
I have one of these 220v "garage heaters". I welded up a small stand for it and put cheap casters on it. I made a 20' extension cord and when it gets cold I dont try to heat the whole shop, I just move this around and have it blowing in my general direction.
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Super dumb question: do you insulate a ceiling any differently than the walls? Just rolled insulation and then drywall? The garage isn't actually built yet, but it will be 8' ceiling with some OSB sheets on the joists for household storage. Gabled roof. That sounds doable, good suggestion, thank you.
I have one of these 220v "garage heaters". I welded up a small stand for it and put cheap casters on it. I made a 20 extension cord and when it gets cold I dont try to heat the whole shop, I just move this around and have it blowing in my general direction.
Thanks Joe. And that does it for you? Warm enough where your powertools don't start to sound like they're seizing up on you? I might be able to get away with something like this…
Quasar, have you considered hanging electric radiant heaters above your work space(s). Radiant heat heats objects and not the air. That means that you, your tools, wood, etc. will be warmed by the heater, but the surrounding air will be cold in winter. Here is one, there are many others, but this one has a picture with open studs.
Your electric bill will probably shock you if you do not insulate. Foil faced R-13 would be easily installed in 2×4 stud bays 16" on center. I am not sure, but I think R-19 foil faced insulation will fit nicely in 2" x 6" stud bays. As much un-faced insulation as can fit in the attic joist bays would be very beneficial. If your budget allows, closed cell spray offers more R value per inch and seals up cracks and crevices better than fiber glass and requires no vapor barrier. But if I am not mistaken, spray foam insulation needs to be covered with a fire retardant material, either sprayed on the foam after the foam has cured or by a layer of drywall. Covering the walls with drywall would probably be a good idea in any event. If paper or foil faced insulation is used on the walls, the paper or foil can tear easily in a shop environment and compromise the vapor barrier that the facing provides.
On the other hand, if the garage door is not insulated, I am not sure how much benefit one would get by insulating everywhere else. I lot of heat can be radiated to the outdoors by a metal garage door.
I elected to heat my 2 car garage workshop with three 1000 watt 240 volt 3400 BTU ceiling mount radiant heating units. These were placed on a dedicated switched circuit. I ran 10-gauge cable in the event I ever wanted to add a fourth heater. An in-line thermostat allows the heaters to come on and off automatically. My understanding is these heaters use infrared lamps which heats objects in the shop and the objects heat the air, making them more efficient than resistive heat and less of a fire hazard. In Ohio winters, the insulated shop remains comfortable. Since the heaters are ceiling mounted, they are always out of the way. On the downside, it does take a little time (generally an hour or so depending on the outside temperature) for the shop to come up to temperature.
If you are interested in these heaters, I posted a review at
The rule is always to insulate first. As mentioned, heat rises, so insulating the ceiling has the most affect. But walls are still critical.
In your case of wanting to retain the few inches of wall cavity space, it is a trade off. There is some insulation created by the exterior construction materials. So there is always a heater big enough. And if you are only going to be heating it up on a Saturday afternoon, then perhaps just getting a big portable kerosene heater of some sort might be okay. Probably the most BTU's for the buck. Though anytime you burn something like this, you will generate water as a combustion product. But it tends to be dry in the winter, so how much this will be an issue, I don't know.
If you really, really can't give up those few inches (and I can't see how this could be that critical), maybe at least put in some rigid foam insulation. Even something as thin as 1/2" will add some significant R-value, compared to nothing. Get the kind of stuff with the foil and face the foil out to where you can see it. That will reduce radiant losses to the cold walls.
Also, do what you can to minimize air leakage. Modern garage doors seal pretty well, but make sure it is fitting properly.
Also, if the garage isn't built yet, build a bigger garage.
Chicago winters are brutal, insulate everything first. As much as you can afford to put in. Proper insulation will allow you to get a smaller heater ( less expensive ) and will slash the operating cost. The long term utility cost will offset the insulation cost.
There will also be a nice level of comfort provided by insulating first.
Living in WI, I can relate to the weather variables you have. Insulate the ceiling as much as you can, as others have said, it's where the most heat goes. Next do what you can to prevent wind infiltration, wind based heat loss is huge, rigid foam sheets placed between the studs and caulk ed will help a lot with minimal loss of space. Ventilate the hot air out in the summer. Proper roof vents help with the heat in summer, but also prevent frost issues inside the place when heating areas below. I used to use a window a/c unit during the really hot days. I also used to use a lp fired wall heater in winter to maintain a min. of 50 during the winter. This was enough to keep the tools from rusting and sweating. Last but not least, a cold floor can be an issue. Get some rubber floor mats for comfort. They will help your joints as well as help keep feet warmer.
While I was working on my yet to be finished workshop this winter, I'd use a propane shop heater for 10-15 minutes in my uninsulated shop. I didn't have any roof vents yet, so I didn't want to run it too much. I also used an electric space heater to warm some gloves, and provide a little warmth. After working for about an hour, the attic space warm enough that it didn't bother me much. That said, There is no way I'd want to do that and actually work on stuff…
I'd say figure out how to do with out at least some of the wall space, and insulate so you don't spend a fortune on heating. Keep in mind that you're already behind with the garage door, as it's pretty much impossible to insulate it to the same standard as a wall, and the air leaks around the edges isn't insignificant either.
4 can you at least insulate the ceiling? That will help a lot while you are out there in the cold.
Brian
- bbasiaga
Super dumb question: do you insulate a ceiling any differently than the walls? Just rolled insulation and then drywall? The garage isn t actually built yet, but it will be 8 ceiling with some OSB sheets on the joists for household storage. Gabled roof. That sounds doable, good suggestion, thank you.
Same way. If you don't want to use the top for storage, you can blow insulation up there. Super cheap and just as effective. But the rolls between the joiists works just fine.
One inch of double foil face insulation board(like Tuff R) will give you approx. the same r value as 3 1/2" of fiberglass and still give you some storage between the studs. You can also use it on most garage doors. Most codes call for it covered some don't if the foil is intact. You would have to check what your code calls for in a garage.
What is the total per KWh you're paying for electricity, that will help you decide? Mine's not terrible, but not cheap either, the taxes and distribution are ridiculous, but a bunch of shovel leaners that are only worth $6 - $7/hr still need corvettes so somethings got to give.
I've been there and can honestly say don't bother running an electric heater without insulation. Unless of course you use JoeinGa's method.
I had an electric forced air unit given to me so I installed it before insulation. That first year, I used it as I worked on the rest of the electrical, drywall backers, etc. When the electric bill came in I shut it down, "re-gifted" it and revised my floor plan to fit a small wood stove.
I live in the same region and have an attached, un-insulted garage. My shop is not in the garage. However, I sometimes need to heat it for a day and use a propane torpedo heater. It will get is reasonable but gets cold very quickly when I turn it off.
I think the cost to heat with electricity will be very high. Natural gas would be better but without insulation will be costly.
Thank you everybody, this is a wealth of good information. I need to do more research but the idea of rigid foam boards between the studs is really promising. You guys are very kind for taking the time to educate. Thanks again!
Since the garage is not yet built, perhaps the Styrofoam insulation could be installed on the exterior. If this is not possible or you elect to install Styrofoam insulation between the stud bays, you could cut the Styrofoam with a sloppy fit, leaving a gap of no more than 1/2" and no less than 1/4" between the foam board and the framing Then, to tack in place, minimally expanding spray foam (window and door spray foam) could be sprayed between the foam board and the framing. This would form a tight seal and hold the foam board firmly in place.
I drywalled the ceiling on my garage and blew cellulose into the attic space it created. The walls were already drywalled, but some of the cavities were not insulated so I cut holes in them and blew cellulose in them too. I also replaced all doors and windows with insulated equivalents and was careful about weather stripping. It is now comfortable to work in there during all seasons (here in CO) without any special heating, though I do have a radiant infrared heater above my workbench for the coldest days.
An usinsulated metal garage door is easily insulated with XPS foam cut to fit inside the g-door panels. Any gaps may be filled with low-expanding spray foam. If code disallows exposed foam, cover it with sheet metal. Better: swap out the whole door with one that is insulated. Make sure the door gaskets seal tight.
If your shop windows are not up to insulation snuff, and new ones are not in the budget, build XPS-insulated interior shutters that may be closed at night to keep heat in. Leave them open by day to let in light, especially when the sun is shining, which will help with the heating.
I have a 50000 btu big maxx gas heater. I have insulated my detached garage that is 30×33 9' ceiling. I have R19 in the walls and R30 in the ceiling. It cost me $10 extra a month to keep the garage at 68 all the time. If you have natural gas available I would go that rout. It is the least expensive option. I live in northern Indiana so my weather is very similar to yours.
No amount of insulation can compensate for the heat loss when the garage door is open.
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