Originally Posted by cjr1881

2-3hp would be unnoticeable. Rpms go up at idle and I hear a big difference in my exhaust note when driving as my engine is more labored. If you are in touch with your vehicle's behavior at all you will notice lack of power and it is definitely present. I know when I feel sluggish I look down and sure enough the a/c is on. I wouldn't notice if it were only 2-3 hp. Searching on the net I have seen figures 5-15. I think our cars are on the high side or I am just very sensitive to noticing power change.