Maintain your equipment to prevent future problems and unwanted costs. Keep your cooling and heating system at peak performance by having a contractor do annual pre-season check-ups. Contractors get busy once summer and winter come, so it's best to check the cooling system in the spring and the heating system in the fall. To remember, you might plan the check-ups around the time changes in the spring and fall.
EnergyStar - U.S. Environmental Protection Agency - U.S. Department of Energy