Radiant Heat in Garage?

[Freerunner]

I'm building a house in the mountains (8400') in Montana and the whole house will have radiant heat. The builder also suggested extending the radiant to the garage because the cost would be insignificant compared to the overall build. The garage will be 1000 sq ft, 2 bays for the vehicles and the 3rd bay for my "toys". I want the garage heated 24/7, but the last house I had (in WI), I had a propane blower which did an excellent job keeping the garage warm.

My question is how efficient would the radiant heat be, considering that the garage doors would be letting a lot of cold air in when opened? I realize heat recovery might be longer, while the propane heat recovery is much quicker.

 

[2011laramie]

Proper Humidity control would be a bigger concern for me with garage slab heat vs heat recovery time.

 

[Randy in Maine]

That is how I did my 40x28 garage made of SIPs.

Insulate the slab with 2" of rigid foam and a 6 mil vapor barrier under the slab. My 1/2" pex is placed about every 12" OC and is fed 120º warm water from my house propane fired condensing boiler about 25' away. I keep it 50º in there all winter. I have 2 manifolds in a dividing wall for the radiant floor heat in and out back to the boiler. Everything runs underground in 4" Sch 40 conduit.

I do have a dehumidifier and ceiling fans when I need it. I also ran hot and cold water out there for use in garden hoses.

 

[ripperd]

Its not going to be cheaper to construct or operate than a hanging unit heater.

It is going to be much more comfortable if you do any work out there however!

One final note, given your location and elevation, you need to plan to handle snowmelt coming off the vehicles. If you don't, your going to have a giant puddle and frozen garage door seals.

 

[Showkey]

OP is a formally from Wisconsin........suspect he is well aware of snow melt in a garage.
My attached garage never drops below freezing on the floor, with no additional heat. Yes, there’s a considerable amount to water from snow and ice melt. Sweep the water out the door is the normal winter maintenance along with the sand and salt grit. Garage Floor drains were not an option in my area.

Ceiling mounted heater might be a cheaper install ? Heater, vent and gas line is less than $1000 all in.

As far working in the garage and comfort........my stand alone shop is heated (NG gas ceiling mount ) to 45-50* and crank the heat up 15 minutes prior to working.

Ceiling forced air heater will handle the dehumidification in cold weather.

 

[HoosierBuddy]

Several of us have radiant heating loops in our garage floor. This is not a new or radical idea.

I agree with points made above that you will need to insulate your garage well including under the slab.

I also think the point is well made that snow melt is an issue (actually true in any heated garage). In my case, there were no civil authorities telling me how to put in floor drains, so mine were inexpensive and work well. However, if you have to build something to code, you may have issues as they are concerned about gasoline or oil going down these drains....which has lead to all sorts of issues getting them installed.

If you do install floor drains, you then face the question to either slope the floor to the drains or not. I did myself, but this causes issues at times as my garage floor isn't perfectly level (biggest issue is when doing alignment work on a car....as you need a level floor).

Good luck.

Phil

 

[Freerunner]

Several of us have radiant heating loops in our garage floor. This is not a new or radical idea.

I agree with points made above that you will need to insulate your garage well including under the slab.

I also think the point is well made that snow melt is an issue (actually true in any heated garage). In my case, there were no civil authorities telling me how to put in floor drains, so mine were inexpensive and work well. However, if you have to build something to code, you may have issues as they are concerned about gasoline or oil going down these drains....which has lead to all sorts of issues getting them installed.

If you do install floor drains, you then face the question to either slope the floor to the drains or not. I did myself, but this causes issues at times as my garage floor isn't perfectly level (biggest issue is when doing alignment work on a car....as you need a level floor).

Good luck.

Phil

All, thanks for the feedback. I will have floor drains under each of the three bays. Not too concerned about the slope of the floor affecting any work I do.

 

[kj_mustang]

I have radiant in my attached 2 car garage. It is well insulated with 2 x 6 walls and insulated garage doors. Recovery time is not an issue after the garage doors are opened. The mass of the floor keeps the room temp fairly stable. I kept mine at 58 F last winter and it was great and didn't run that much to keep it at the set temp.

 

[jack stand]

I'm building a house in the mountains (8400')

My question is how efficient would the radiant heat be, considering that the garage doors would be letting a lot of cold air in when opened? I realize heat recovery might be longer, while the propane heat recovery is much quicker.

There is no "recovery" with radiant, the mass of the heated slab will overcome the cold air almost immediately and you'll look back at your old garage's propane and laugh at it.
100% recommend going radiant or at least do the prep work while your at it with the house.

 

[Randy in Maine]

All I had to buy for my 1200 square foot shop set up was 1 linear feet of 1/2" pex tubing/square foot of building ~1200 feet, 2 manifolds for 4 loops each, and a thermostat to tell the zone valve controller when to open.

Not as fancy as some, but it works really well. I just have one Taco 007 pump for the whole house set up that runs the 3 zones from my Baxi boiler.

 

[Jackfre]

Radiant is fine. The alternative propane heater would be a Rinnai EX-38.