HVAC guys here? Garage?

[Diggin It]

My only question is what kind of insulation do you have and what size is the garage if 112,000 BTU's won't keep the space at 60?

Also wonder what your electric rate is because running 23 amps on that portable heater on high is going to use some juice.

Ain't NO way I'd be using electric to heat a shop/shed/barn. LP, NG, Kerosene, waste oil, wood ...... anything but electric.

 

[Sigarms]

Ain't NO way I'd be using electric to heat a shop/shed/barn. LP, NG, Kerosene, waste oil, wood ...... anything but electric.

Neither would I.

Worst case to heat an area further away from the ductwork, I'd close off some bottom registers, run a airtite collar off the duct work and run wrapped hard pipe to the area needing heating. Use the furnace you have. 112,000 btu's of heat can generally heat a decent insulated whole house.

 

[Fuddy1952]

It's 6100sq.ft. 2 story, in sections. I'll soon add another 1,200. That's not including overhang areas.
This heater I installed today. I'm very happy with it. I fabricated a bracket using 1/4" steel at the top, eye bolts, chain and another bracket in back so it tilts down.
I used 10 gauge and a 30 amp breaker.
The front switch one direction the fan runs continuously, thermostat cycles heater on low. Other position the thermostat turns fan and heater on high. It looks like thermostat will go as low as 38F.