i bought the re-verber-ray made in detroit. 50,000 btu 30' tube. I actually ordered the 2-stage residential unit, but this is what showed up. commercial unit, dx model single stage. takes a few weeks to get.
the good: at 57 degrees your roasting, so you can keep the temp lower. your tools and vehicles are warmed up, not just the air.
when it turns on its quiet and doesnt blow anything around.
when you open the garage door, it doesnt seem to affect the temperature inside so much. the whole place seems its the same temp. (my buddy has a unit heater, same size barn, and seems cold in his barn at 60 degrees.
bad:? it takes over an hour to get to 55 from 42, not exactly sure on time yet, may even be two hours.
i have a finished and insulated 32' x50' pole barn. i keep the heat at 42 deg full time, until i plan to go out there. (live in michigan). this is my first winter with it, so i was turning it up to 55 just to go out there and play around. (57 degrees is roasting and your taking your clothes off, just like the sun shining..) well, after a few weeks i realized it was using more propane than id liked. i have 140 gallon tank ( they fill it to 84 gallons, so at 2.50 per gallon, its around $250 delivered) i used most of this in one month. I could probably get two months out of this after learning how to use it more effectively. clean,safe heat is definitely worth $100 per month to me, but $200 seems a bit errational for me to work on my toys.