I use those interlocking rubber mats and noted it helps keep my feet
from freezing (concrete floor) in addition to the comfort when
Those circular kerosene heaters (http://www.yourheater.com/dh2304.jpg
do all right but send most heat directly UP over themselves. I use one
in my basement and can operate it for 24 hours on a fill and keep the
basement at 66 when the outside temps are dropping below thirty.
In my insulated garage, I can get by with a little ceramic heater or
one of those electric heaters that have the "ribbons" of metal and a
little fan to keep the chill off.
I'm not too sure I would want one of those Propane infrared heaters
with all the saw dust generated on a good day and that MODINE HOT DAWG
HD30 - $479.00 thing would buy you a lot of insulation.
You may be able to rent a construction heater and try it out before
plopping down the $279 or so plus the cost of the propane and tank
(another $50?) - again, that would buy a lot of fiberglass bats.