Satisfactory horsepower for an ordinary sized garage door ranges from ½ to 1 ½ hp. A ½ hp garage door opener motor is adequate for boosting and lowering nearly all door varieties. The SilentMax® 1200 ultra-quiet belt drive garage door opener with 140V DC motor gives an opening velocity of http://felixalrk750.bravesites.com/entries/general/consumer-reports-garage-door-openers