Homeowners

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Central Cooling and Heating System Maintenance

Change the air filter. Check the filter and change it if it’s dirty, or according to the manufacturer’s recommendation. Regularly changing the filter keeps dust from collecting on the evaporator coil fins. Keeping your filter clean also can cut energy consumption 5 percent to 15 percent. Turn off the power to the furnace before pulling the filter out so the blower doesn’t come on and blow dust throughout the system. Be sure to position the filter according to the manufacturer’s instructions.
Clear away debris such as leaves, grass, weeds and plants that block airflow through the outdoor condensing unit, which is the large metal box in your yard next to your home. Anything that collects on the unit’s fins will block airflow and reduce its efficiency. Grass clippings thrown by the lawn mower are particularly common offenders.
Occasionally clean the outdoor condensing unit by spraying it with a water hose.
Check to make sure air conditioning vents inside your home are not obstructed by furniture.
Check to see that vents in the house are unobstructed. Air in your home needs to circulate easily through the vents. Your furnace works less when heated air is not blocked and the cooler air can circulate back freely.
Close off unused rooms and close vents in those rooms.
Set the fan speed on high except in very humid weather. When it's humid, set the speed on low; you will get less cooling, but the air circulation will make it feel cooler.
Hire a professional to service your central cooling and heating system. A well-trained technician will find and fix problems in your central cooling and heating system. However, not all service technicians have the same level of training. Look for a technician that is certified by North American Technician Excellence (NATE). Click here to find a NATE-certified technician in your local area.
Check the filter and change it if it’s dirty, or according to the manufacturer’s recommendation. Regularly changing the filter keeps dust from collecting on the evaporator coil fins. Keeping your filter clean also can cut energy consumption 5 percent to 15 percent. Turn off the power to the furnace before pulling the filter out so the blower doesn’t come on and blow dust throughout the system. Be sure to position the filter according to the manufacturer’s instructions.

Be sure to insist that the technician:

Check for the correct amount of refrigerant and test for refrigerant leaks.
Capture any refrigerant that must be evacuated from the system.
Check for and seal duct leakage in central systems.
Measure air flow through the evaporator coil.
Check the accuracy of the thermostat.
Verify the correct electric control sequence and make sure that the heating system and cooling system cannot operate simultaneously.
Inspect electric terminals, clean and tighten connections, and apply a non-conductive coating if necessary.
Oil motors and check belts for tightness and wear. Loose belts can increase furnace operating time. Replace frayed or cracked belts. Two or three drops of oil in the motor will keep it running smoothly. (Sealed blower motors require no lubrication. If you have questions, check your owner's manual or call a heating professional.)
Make sure blower doors are replaced properly. This keeps combustion byproducts such as carbon monoxide separate from the warm air circulated through your home.
Check to see that the exhaust flue to the outside is clear of obstructions and in good condition from the furnace to the roof cap with all connections securely fastened. A contractor will check it by removing the flue cap near the furnace and water heater and looking through the flue to the outside. The flue cap needs to be replaced securely. If the furnace or water heater is in an enclosed room or closet, they need to get plenty of air. These appliances need ten cubic feet of air for one cubit foot of natural gas to operate properly. Furnace rooms or closets should have door louvers or vents or a duct directly to the outside to provide sufficient combustion air.