Don't heat the garage. Put high R value insulation on the garage ceiling and make sure there is no air infiltration into the space between the garage and the house. Seal up all the cracks and holes.

Heating a garage is a waste of money and actually encourages your car to rust out in the winter.

i agree with sharon, insulate but do not heat. my insulated garage stays about 20 degrees warmer than outside temps during the winter.

If I could just comment her and maybe get some feedback on this topic. I have a somewhat related issue.

I hade my master bath toilet and the cold water feed for the washer in the adjacent laundry room freeze up twice last year. The master bathroom bumps out 18" from the rest of the house. These pipes run up the outside wall and thru the subfloor of that 18" bumpout section. FOr whatever stupid reason, the builder's design didn't put the piping on an interior wall. The attempted fixes last year included adding more insulation inside the soffit of that bumpout, and then adding an second wall vent in the laundry room behind the washer so that warm air could circulate behind the wall, and that was supplemented by encasing the pipes behind there with insluated foam board of some kind.

Anyway,the same pipes froze again last night. BY the time my wife got the builder's site foreman over to the house, the pipes thawed out. Toilet bowl filled back up and the cold water runs again on the washer. How that happened overnight is beyond me. It had to be in the teens during the overnight, if not colder. Well, he first tried to blame the frozen pipe situation on the fact that he says we leave our garage door open for great periods of time. ThatÂs crap, IM! How can that seriously be a contributing factor to the pipes in question?? My master bedroom is fully above the garage space (it's not abnormally cold and the proper insulation is in the garage ceiling, according to code), and adjacent is the master bath, and adjacent is the laundry room. The feed pipes for the toilet and washer are located about 14 feet to the side of the garage area on the backside of the house and in the area of the first floor ceiling/second floor subflooring. And he's claiming that cold air from the garage is causing or contributing to these pipes freezing? It's not like we leave the garage open for extended periods of time in freezing weather, and we certainly don't leave it open overnight! The master shower and jacuzzi tub don't freeze up, and they are phjysically closer to the garage than the toilet. GIVE ME A BREAK!!! In addition to that, IÂd also point out the fact that the toilet area of the master bath is directly above the first floor pantry, which is extremely warm, with a floor vent in there and the pantry door closed most all the time. All that warm air in the ceiling of the pantry. What a real jerk this guy is, trying to peddle this lame excuse as the contributing factor to the pipes freezing!! Two different plumbing contractors that have worked for the home builder in the past year, they both said the piping didn't belong on the outside wall. But the foreman says they aren't going to tear up the tile flooring and walls to move the pipes. They want the issue to be shored up via insulating methods.

Any comments? The garage excuseby the foreman is bull$hit, right?

Right now it is about -15 plus -20 windchill. All plumbers
and renovators charge at emergency rates. I will definitely
get my garage ceiling insulated on top of the existing
drywall ceiling. My home builder is Arthur Blakely, one of the most reputable residential home builder in Ontario. But
we find that his workmanship is so bad all over the house.
He sold the new Model Home to the previous owner two years
ago. The new home warranty does not pass to the second
owner and we are stuck with hundreds of deficiencies
which we are finding out gradually now after being here
for six months. In the spring months the weather was nice
and none of the problems with roofing, downpipes, windows,
insulation, poor plumbing work all over, etc etc were visible to the Home Inspector.
andy2007

Saw something similar to this on Holmes on Homes (HGTV) not too long ago where a couple had bought a new house I think it was in Toronto. Anyways Mike H pulled all the drywall down in the garage near where the upstairs bathroom was and there wasn't any insulation in the space at all.

Whatever you do, you should do it quickly. Our master bath is over our foyer and actually inside the house, however where it is situated is not under any bricks. I guess the roof line ends and the foyer is actually just all joists and drywall and was SUPPOSED to be insulated up the ying yang because of the location. Well two water pipes burst this past week and completely flooded my main floor and basement and there is now thousands of dollars worth of damage and we are in a hotel for the next few months.

New builder, yep, 2.5yr old house.

Our garage is detached, but PO insulated it like crazy. It has the fiberglass insulation between studs, and then instead of drywall to 'finish' interior walls and ceiling and walls he put the foam insulation sheets up like those that go on the side of a house beneath vinyl siding. Like the poster above, our garage is a good 20 degrees warmer (even on most bitter days) than outside temp.

Not only do you want to insulate the ceiling of the garage/floors of the above rooms, but also seal any cracks in the garage so carbon minoxide doesn't get into the house. Holmes on Homes was just on again and I thought of your post immediately. He used that spray foam insulation to go around everything, all the pipes, etc. They said 4 inches (which they used) of thickness was equal to a 29R value, and that 25 was all that was needed.