1/3 HP should suffice for all home needs. If you were going to use it in a pro shop, they guarantee it, even then, but there I'd use the 1/2 HP version. I didn't know how much use I'd get at the time; so when I bought mine 15 years ago, I bought the 1/2 hp version. Good investment - better than buying 5 bowling balls for the price of 1.