On Sat, 12 Dec 2009 18:52:37 -0600, Vic Smith wrote:

Took one of the 23000 BTU heaters out to the garage last night and fired
it up. Burned clean and hot. It was 18 F. Good to warm your hands
only.
If you're 18" away from it you feel nothing except 18 F. Problem is the
heat goes straight up from the heater top and past the rafters and out
the roof vent.
Tomorrow I'm going to climb up on the rafters and block the roof vent.
We'll fire up both the kerosene heaters and do the alternator and water
pump on the Grand Am. See if the garage warms up a bit. Supposed to be
about 30 F tomorrow.
I'll bring a thermometer out there to see what's really happening. Just
having that flame burning and putting your hands over it make you feel
warmer, but I don't think it did a damn thing to warm up the garage.
Have to measure that.
Garage isn't real drafty, but there's no insulation. These heaters might
provide only hand-warming and psychological comfort only out there.
We'll see.
Anyway, I want them for the house in case of a power outage, so they
still have that value regardless of what they do in the garage.

--Vic

You could put a tarp or polyethylene sheeting across the rafters to
shrink the size of the garage.