Garage Heat without Exhaust / Vent

[lawfarm]

I have a 2.5 car attached garage (about 650-700 square feet). Insulated 2 car wide garage door, insulated walls, and R45 ceilings, with 5/8" drywall over it. Door is 7.5" high, ceilings inside garage are 10'. I'd like to have heat in the garage for: 1) always leaving it on low in the winter, to prevent freezing in the garage; and, 2) being able to turn it on and warm up the garage to permit working in there (or hanging out in there) in the winter. I wouldn't mind if it required some planning ahead for heat (i.e. turn on the heat and have it be comfy in there an hour or so later. I live in Northern Illinois, so winters can get pretty rough from time to time.

My problem: I don't have a good way to run an exhaust/vent for the heater. I anticipate using Natural Gas, but the sidewalls of the garage are going to be very, very difficult to use, as would running a vertical exhaust through the living space over the garage...so I'd really like to go with a ventless option. That seems to leave either a radiant option, or something akin to this:

http://www.homedepot.com/webapp/wcs...langId=-1&catalogId=10053&productId=100593846

Any thoughts on the suitability of one of those for garage use? I anticipate mounting whatever I get on the front wall of the garage. Any other good suggestions?

 

[PAToyota]

The biggest problem with "ventless" NG heaters is the water vapor that they spew into the air - to the point of causing rust on tools and other moisture problems.

 

[lawfarm]

Yeah, I'm aware of that issue. However, I was thinking that in an application like mine, where nearly an entire wall is door, and the door is opened a couple times per day...with the heater being left on low most of the time...it might not be that bad? That's why I was seeking experience from others.

 

[PAToyota]

Unfortunately, you can't retrofit it, but for new construction this would be a perfect situation for a radiant floor. The thermal mass of the floor would mean that you would not lose all of your heat when the garage door was opened and the room would warm back up more quickly after the door was closed again.

Even with the door being opened and closed, you are likely to experience moisture problems and the heat/cool cycles will likely cause greater condensation.

 

[timgr]

How about electric?

Even with a ventless gas heater, you still need to take O2 from the air, and that's in addition to the CO2 and water vapor you create. There has to be some air infiltration: the building has to be leaky or the occupants will suffocate. I don't see any way to solve it except electricity, or locating the heater outside where you can heat water or something and then running the warm water to a radiator. Without combustion...

 

[Torque1st]

Ventless: Been there done that... Don't waste your money, the fumes and humidity make for a very nasty place to work in.

Electric heaters are about the only way to go for occasional heat.

There are some thru-the-wall electric heat pump type units like motel/hotel units that can be used, -they are expensive to buy but cheaper to operate.

 

[MNMuskie]

Venting wasn't reasonable for me so I put in a hanging 5000w from Northern Tool. I think I got the mid-grade model and was pretty affordable. It works great for keeping my insulated 2-car warm through the coldest MN temps.

 

[Torque1st]

MN doesn't have temps... There ain't no way to read a thermometer when all that is in it is a shriveled up grain of sand in the bottom of the bulb!

Welcome to the Garage Forum. At least now when you go outside you don't have to worry about a couple of skeeters carrying you off.

Just watch for pressure breaks when you are out driving and eat a walleye for me.

 

[bomber]

my old ventless did a great job of two things . . . . .

1 -- heating the garage
2 -- creating a micro climate

Having had enough of jungle living in the very early 70s, I gave the ventless away, and got a vented (horizontal stock out near the peak of the roof, back side, not visible unless your cralign in the woods)

after a day in teh garage, even if I opened the door a couple of time to clear the moisture (and attampt to heat the county), moistue would still condense over night -- a lot of moisture . . . . . . .

YMMV, though

 

[russlaferrera]

In some parts of the country, electric is the way to go. Do a estimate. You may be surprised of the results.

Have you looked into a high efficiency heater" Some exhaust with a PVC pipe, others use a power exhaust fan. With this you may have to just use a dryer vent thru the wall.

 

[lawfarm]

How do I go about estimating the operating costs? I haven't found any (functioning) calculators on the web...

 

[russlaferrera]

How do I go about estimating the operating costs? I haven't found any (functioning) calculators on the web...

Google "www.warmair.net" under efficiencies Plug in your cost of elect. and it will calculate per 100k btu, times the amount of BTU you need.

 

[lawfarm]

From my calculations, natural gas is $.016/cubic foot, and electricity is $.12/kwhr.

Based on that, warmair estimates $3.16 per 100,000 btu for electric, and $1.86 per 100,000 btu for natural gas. That makes this a pretty straightforward decision.

Based on the size of my garage, it looks like I'd need about 100,000 btu to raise the temperature 60 degrees...so basically, $1.30 difference between gas and electric every time I want to change the temperature by that much (which is quite a bit...maybe more reasonable to say $.65 every time I raise it 30 degrees).

That seems to make my decision pretty straightforward...but I'm also thinking, based on comments above, that I need to reconsider my 'no venting' rule.

 

[rickairmedic]

Lawfarm you wont need to raise the temp that far for an insulated attatched garage . My current outside air temp is 40 degrees and its 60 degrees in my attatched 2.5 car garage with no insultion in the walls and a plain metal non insulated garage door. A 60 degree rise would either cook you or cause the heater to shortcycle. I would say look into a high efficiency forced air furnace 90% which would use PVC pipe for the flue and could be run right out the wall of the garage . Mind you the end of the flue pipe needs to terminate at least 6' from any opening ( door or window) .

Rick