Cool, thanks for the info guys.

Next question...

I need to free up some space in the garage and want to put the two smaller compressors in the attic. Obviously the smallest will be air storage only, but the middle one still works. I'm thinking if I put it in the attic, I can put in a dedicated 20A breaker for it, and either turning it on and off with the breaker (breaker box is in the garage) or wiring in a separate switch in the garage for it so I can just leave the actual switch on the compressor on all the time.

So, the question is, how do I mount the compressor in the attic so that it doesn't vibrate the ceiling apart, or if I put it up there, should I just use it for air storage only?

Only options I can think of is put it on some thick rubber mounts with it sitting on the ceiling joists, or suspend it somehow from the roof joists so its not touching the ceiling at all. Only thing is, its kind of heavy...