Power
If you are considering heat alternatives, especially for your garage, take a look at FUJITSU Mini Split systems.
Heat and air conditioning in one unit. All electric. Very efficient. works down to -5 degrees.
One unit hung on wall inside up high. Power unit hung on outside wall.
2 refrigeration lines running vertical outside with cover over it. Unit is charged, so no gas has to be added at start up. ( Be sure to double check nut connections, had to change them to prevent leaks.)
Can install in one weekend with 2 people.
220 volts, 11 amps draw at max.
Inverter DC variable speed fan and power unit.
Remote temperature control, no wires.
Can get larger ones with up to 4 different heads and separate controls for each one for whole house use.
I already had a hanging natural gas heater, Reznor BULL DAWG, that is also high effiency. Fujitsu is more efficient, cost less.
Set it on AUTO, 70 degrees year round, and forget it.
Midwest location.