13 foot high ceiling - what to do?

[internetdude]

I'm trying to figure out the perfect heater for my garage. Here's the specs:
- attached 21x24' (504 sq ft) double car garage
- Two car doors, both steel insulated
- Outside walls 2x4 construction with fiberglass batt insulation (R12 I think)
- Ceiling will get insulation blown in soon (the old newspaper or whatever type, not fiberglass)
- 6mil poly on all outside walls/ceiling, tuck taped, sealed nicely (2 year old house)
- Tall ceiling, we're talking about 13'
- Interior finished with sheetrock and painted (walls & ceiling)
- Climate: Cold, Saskatchewan, Canada

I basically want to run a heater on a "low" setting, perhaps just above freezing all the time. I'll only need to turn it up maybe once a month for a few days to work on vehicles/projects/etc. Otherwise the heater is just there to take the chill off. I do have a hybrid car (Prius) so keeping it's battery pack warmer than -40 won't hurt anything either ;-)

Right now I'm mainly considering a Big Maxx / Hot Dawg 45K natural gas hanging heater since I have nat gas to the house.

My questions are this:

1) With a Big Maxx/HotDawg nat gas hanging heater, is there a wire to run the fan only?
2) Based on my usage mentioned above should I consider a radiant tube (overhead) setup? I understand they're more efficient but I've also read that if you need to crank them up to warm things up they take a while to make a difference in the room. So they're better to just "set it and forget it".
3) The local plumbing shop recommended a 45K BTU heater, problem is when I check the technical specs for them, they say the maximum mounting height is 10'. I don't understand why... however I hear you can get a 2' drop kit that will bring it down to about the 11' high mark which should be acceptable.
4) Would you recommend I also install a seperate ceiling fan (or just run the fan in the heater) to help circulate air? I'm aware all the hot air will be up high where it's not needed.
5) My garage is 21' by 24' with 13' ceilings - total of 6552 cubic feet. Is 45K BTU good or should I go for 75K BTU?
6) Do you think all of these questions are moot if I simply run the fan in the overhead heater to circulate the air?

I'm not overly concerned about price. If anything the cost to run it is more important than the purchase price. I want to keep my monthly bills low even if it costs more up front.

Thanks everyone.

 

[bmwpower]

Is it already built? If not, go radiant.

If it's built, you definitly want something to push the hot air down. I have a forced air heater in the attic, but it does a poor job of getting hot air down. That's what I use 2 ceiling fans for. In the winter, the fans run all the time. The tstat is set to 40*F or so to keep stuff from freezing. The fans push the hot air down.

My heater is 100k (80%). My ceilings are 14 foot high.
100k does wonders when you want quick heat. You garage is somewhat smaller, but how efficient are those heaters?

 

[internetdude]

OK, well it's a year later. I guess I should have updated this thread sooner.

I went with the Modine 45K natural gas unit. I mounted it using those rods that go up to the ceiling joists so it is hanging down close to 2 feet. I wired the thermostat up so I can manually run the fan on the unit. I had fiberglass insulation blown in up top. Everything worked out great.

Being able to turn just the unit fan on in the winter is great because when I go to a carwash, I just park in the garage and let the fan run for a few hours. I can even leave the car doors open so they dry instead of freezing shut the next time I go out.

I keep the garage temp around 4 degrees Celcius. I just crank it up an hour before I'm going to be in there doing an oil change and it's all good.

 

[FThera]

I have a 24 x 34 here in Minnesota with 11' ceiling and a 40,000 btu unit heater does just fine. It's also the smallest size you can get in a gas unit heater. I keep it set at 40 most of the time and just turn it up when I'm going to work or wash the car. With it set a 40 I don't really even notice much of a difference in my heating bill over not running it. My walls ar R19 and the ceiling R30. The ceiling could have more insulation though.
Get the best insulated doors you can afford. Mine are 20 years old and NOT the best insulated, and are probably 1/3 of my heat loss.

 

[Dragster Racer]

Sorry you didn't get many responses before. I think you made the right choice. I keep the ceiling fans running all the time in the winter in the shop. Why heat the heck out of the ceiling? Push the air down and the thermostat will kick off. Plus it knocks out the moisture.
Glad it worked out for you.