its more about the cfm, than the hp or psi(ie how much cfm at 90psi)...cause that is what most air tools run at...i hope you have not purchased one yet...you should look at the tools you will be using the most and get one that produces enough air for the one that consumes the most...it will usually be the Impact wrench, but since you wont use that constantly it shouldnt soncern you that much...hope this helped...lmk if you have anymore questions, cause i did a lot of research on this before i bought mine