Electric fans do use some horsepower. They are powered by electricity provided by the alternator. The alternator is driven with horsepower provided by the engine. Nothing is free. :?
Yes, yes that is technically true. The alternator is already being spun by the engine. The additional electrical load on the alternator to power the fan(s) will use some miniscule amount of HP. Last figure I saw for HP loss for running an alternator on the strip was 2 HP. Thanks for correcting me.