Al, you are right that this isn't accurate. Just remember that the 746 IS an accurate number, but the innacuracy comes from the inefficiency of the electric motor itself. Rated HP X Service Factor X Pump Hours X Utility KWH rate will give a close estimate of daily cost. To be very accurate, Motor Current X Motor Voltage X Pump Hours X Utility KWH rate divided by 1000. It's a little easier to do the HP one in your head.