Overheating is a common cause of motor winding failure that is caused by start or stop. A motor that is exposed to excessive amounts of heat may encounter a rapid deterioration in the winding insulation. For instance, a motor that has a predicted lifespan of 20 years may have its life reduced to just one year if it is continually subjected to high levels of heat, which is about 40 C above the recommended temperature. Overheating can be caused by other sources besides start and stop including overload, environmental factors, poor power conditions, and high effective service factors.