This motor or pump/motor is a heavier motor than most OEM productions. If you have an Emerson motor, you have the standard duty. We have found more success with this heavier motor. It's similar to buying a larger motor for your car.  If you are in a warmer climate, the standard duty is fine. If not, we recommend the heavy duty. The pump/motor is assembled in-house but has the standard warranty of 90 days.