What size of air compressor do I need to run an impact wrench in my garage at home? I will only be using it intermittently to loosen difficult nuts and bolts.

I know I need at least a 5.0 cfm at 90 psi rating. Can I get by with the ones that cut off at only 125 psi, or will the compressor constantly be turning on all the time?

Is it better to go with one that goes up to 150 or 175 psi instead? I was thinking that if I went that route that the cfm would be less important, because by the time the compressor turned on again I would be done using the air tool. I was also thinking that then I could get by with a smaller, like 20 gallon unit.

It seems like all the better compressors require oil. Is it only the home user type units that are oil free?

 

oil free compressions are duky
a 20 gallon would be nice
a tiny one would work but run all the time, and if you used it, you would have to wait for it to fill back up. harbor freight ftw.

 

i have a 30 gallon... i would look into the flow rate of the compressor. mine holds 30 gallons but the motor cant keep up with the air usage when i use air tools so im constantly waiting for it to refill... research that as well its not just about the tank capacity.

 

i have a 80 gallon and i use air tools and paint guns all the time and i dont have to wait for it to fill up with air. it just depends on how much you are going to use it. i would say atleast a 30 gallon.
get one that has to have oil. they last longer.

 

i had a 60 gallon and i loved it never had a problem with it look on craigslist also you can usually find good deals.

 

My wife bought me a 17 gal craftsman (oil-less) last christmas and it has gone strong so far. I use it to swap my tires for autox, getting the bolts out without the the use of a socket wrench, and others. I just used it to polish my EM1 rims instead of using my hands. The compressor was on most of the time, but it was able to keep up with my 6" sander. I only left it running for maybe 20-30 minutes out of the hour. I recommend getting a water trap and/or drier in-line.

 

my compressor is about 3 years old and oil-less and i havnt had an issue