The integrity of your furnace or air conditioner depends on how well it is maintained. At JW Hanson Heating and Air, we offer maintenance agreements to make sure your HVAC equipment keeps you warm in the winter and cool in the summer. Attached is our check list based on what type of HVAC equipment you have. If your furnace or air conditioner are more than 10 years old, it is a good idea to have them serviced once per year. And don't forget...change or clean that filter at least once per year no matter what the age of your furnace or air conditioner.