New garage heating dilemma

[Greg-nwo]

Going to be moving to a new house in a couple weeks and I've been trying to figure out how to heat the detached garage. It's a 24x28' on a concrete slab. I have since found out that they did not insulate under the pad so that adds a small complication to the project. We get temps down to -35C in the winter here with normals in the -20C to -25C range.

I would really love to have radiant in floor but that would require insulating under the floor somehow (breaking it out, pouring a new floor over top)

My other thought was to just put in a pellet stove but I'm not sure how hard it would have to work with the slab not being insulated.

Some of the ideas I've had so far...

1. Break the floor out, insulate and lay pex for hot water radiant heat. We are putting in a new oil boiler for the house and it has enough capacity to heat the garage as well if I had lines run to the garage.

2. Put down something like Insul-Tarp over the existing slab and then pour concrete over pex to do the same thing with our boiler.

3. Put in a pellet stove the way it is and see how it goes. Kind of have a bad feeling about doing anything without taking care of the slab first.

4. Put in a temporary electric / propane space heat and just heat it up a bit when I want to work in the garage. Not ideal but maybe it could work.

5. This is my uncle's idea.... pour a new slab in front of the garage and plumb it for heat then pull the garage ahead on the new slab and use the old slab for cold storage (gardening tools, lawnmower etc. Could put something simple up to put a roof over the area.

The garage needs to be insulated first it is just bare studs now and is wired up with a 100amp sub panel. I probably won't be able to do anything until next year anyway but I've been trying to sort out what I'd like to do in the meantime

Any thoughts or ideas?

 

[ghnl]

Radiant heat in the floor would be nice but I doubt it'd be worth a retro-fit. Heat rises so good insulation in the ceiling & walls plus minimizing any drafts would be the most cost-effective.

 

[Greg-nwo]

Was chatting with a carpenter friend of mine earlier and we sort of came to the same conclusion as well. I think I'll insulate it really well and throw in a pellet stove or something similar.

In floor would be nice but too pricey at this point.

Thanks

 

[skinanbones]

once your isulated and boarded you would be surprised how easy it would be to warm up with the pellet stove. At this time of year i'm sure your could find one for next to nothing, just spend your money on the venting and put it in with some verticle inside and some adjustable lengths so that down the road you can change out to another pellet stove without having to cut more holes in the wall

 

[Gary S]

Unless you are putting in radiant heat in the floor, you don't want your slab insulated in a climate as cold as yours. Up here in the frozen north, my air temperature outside gets down to -40. The ground temperature under the slab is at +30 almost all winter. Insulating the floor would steal heat from my garage.
If you have radiant heat in the floor, it would be profitable to insulate it from the +30 ground. If you heat only the air in the garage, you lose by blocking the +30 from helping you stay above the -40 air outside.

 

[Greg-nwo]

Oh ok, that makes sense and thank for you for the information

So with a pellet stove the garage should be fine the way it is after I insulate/drywall in interior.

 

[klogan121]

I was in a house heated by pellets, and it had a bad odor to it! It was 20 years ago, but do pellet stoves emit an odor now?

 

[nate379]

I agree as well.

My Dad's main garage that he built in 1990 has nothing under the slab. Even when it's -30* outside it will be above 0* in the garage. (don't heat it unless we are working in there).
He has a small wood stove which will cook you out if you aren't careful. Bottom floor is 20x30 I believe with 8ft ceiling.

Unless you are putting in radiant heat in the floor, you don't want your slab insulated in a climate as cold as yours. Up here in the frozen north, my air temperature outside gets down to -40. The ground temperature under the slab is at +30 almost all winter. Insulating the floor would steal heat from my garage.
If you have radiant heat in the floor, it would be profitable to insulate it from the +30 ground. If you heat only the air in the garage, you lose by blocking the +30 from helping you stay above the -40 air outside.

 

[Phuckin' Jim]

If I were you, I would insulate the building as well as you can, then put in a couple of electric unit-heaters.
If you do go the pellet-route, you might want to talk to your insurance broker. Some companies have special rules for solid-fuel appliances in a garage.
Keep in mind, you'll lose about 6-9 square feet of precious floor space with the stove.
Also, compare the cost of pellets with Hydro.
Here is a fuel cost comparison calculator:
http://www.hearth.com/econtent/index.php/articles/fuel_cost_comparison_calculator/
Remember, pellet stoves are generally around 75% efficient. Electric furnaces and heaters are considered to be very close to 100% efficient.

I'm not trying to scare you away from the pellet stoves, but I think it'll take a LONG time to re-coup the cost of the stove and installation.