Oversized Propane Heater (hanging), Usable?

[Aaron10647]

A few months back I stumbled on a Hot Dawg 75k BTU heater for a very good price on craigslist. Now that its starting to get cooler it would be nice to finally install it and have some heat in the garage this winter. The problem is by my estimates, the heater is way over sized for my needs (estimate 22-25kbtu).

Can I still use it? What are the downfalls to running a heater that is too large? Should i re-evaluate my heating requirements and go a different direction?

Garage info:
22'(l)x22'(w)x13'(h)
R12 walls
R19 ceiling
2x 8x8 garage doors (insulated but open interior construction)
1 man door
Shares wall with house w another man door
Location: RI
Usage: intermittent heat during weekends when I want to be in garage

 

[djjsr]

I'm not an HVAC guy but I had an oversized heater installed and found out about "short cycling". Each time the heater came on it only ran about 15 or 20 seconds to satisfy the thermostat then shut off. It works but it's not the most efficient for gas consumption. I think it's because of the gas used to heat up the heat exchanger before the blower comes on.

For example, you would be better off if the furnace came on 4 times an hour and ran a little longer vs. 8 times an hour and ran for only 15 seconds.

 

[brewchief]

It's oversized but not so much that I wouldn't use it if I had it, output will be about 80% of input so 60k output. Being a bit oversized won't hurt when you want to warm it up quickly for the weekend or just to work out there one night during the week. It may short cycle a little but it's a garage not your living room.