The air conditioner typically uses from 5 to 8 hp....

When I constructed an AC for my karman Ghia out of three different aftermarket under dash units... I also used a spring loaded ' normally on ' switch taped to my gear shift lever which I could touch with my thumb... when pushed down my AC was OFF.... not any different from the clutch cycling in a normal fashion .... but it made a huge difference off the line...I already had my hand there shifting... so it was very natural to engage it.