My new (to me) compressor is a 2 stage, 175 psi rated. But it seems to me that one would only set it for 175 psi if you had a tool that needed that much, or if you needed a burst of air at greater than the pump's cfm rating (the extra pressure would be a reserve that you could draw down). In ordinary use of normal pressure tools that don't use more than the pump's cfm, I'd think that you'd set the pressure switch to cut-in at the highest pressure that your tools use and cut-out at some reasonable differential above that. Then your pressure would never be lower than your tools need and energy would not wasted pumping to greater than the needed pressure (pumping from 125 to 150 requires more energy than pumping from 100 to 125). For example, cut in at 100 psi and out at 125.
But, the extra energy in the higher pressure air is recovered when the air is regulated down to lower pressure/higher volume. Not fully recovered, of course, due to inefficiencies. I guess the question then becomes: "Is the efficiency of pumping to a higher pressure that much less than pumping to a lower one?"
What do you other guys with 2 stage compressors do?
Thanks, Bob