Clean excessive leaves and debris that can accumulate in the outdoor unit. First, turn off the electric power to the unit. Then you can remove a side cover and clean out as much debris as possible by hand. Make sure all the screws are tightened well when you replace the cover.
Photo by James Dulley
Q: My central air conditioner gets professionally serviced periodically and is running fine. But are there any simple, low-tech maintenance tasks I can do between service calls to improve efficiency?
A: There are several things you can do to keep your central air conditioner running at maximum efficiency and cooling output. Keep in mind, though, that it’s a complicated piece of equipment, so you still need regular, professional service calls. These units have many pressure settings you won’t be able to check yourself.
My first suggestion—not really a tune-up item—is to run your air conditioner less during the peak afternoon heat by setting the thermostat a few degrees higher. An automatic-setback or programmable thermostat with at least three setback periods (day, afternoon, night) is ideal for this. Air-conditioner efficiency drops when it’s hottest outdoors, so it uses more electricity trying to keep your home at a cooler temperature. Setting the thermostat higher saves energy and money, and it reduces peak electricity demand, which minimizes future electric-rate increases and greenhouse-gas emissions.
The most important factor for efficient air-conditioner operation is getting maximum airflow through the outdoor condenser coils. This airflow cools the hot refrigerant, which then flows back through the cooling coils inside your house.
Clear the area on the grill side of the outdoor unit, where the condenser coils are exposed. Landscaping, shrubs and weeds may have grown up around it. Cut plants and branches back to provide at least 2 feet of clearance. Similarly, don’t rest garden tools or other items against it or on top of the fan air outlet.
Inspect the inside of the outdoor unit for excessive debris by looking through the grill. There will always be some debris (leaves, sticks, etc.), but if it looks excessive, clean it out. Always switch off the circuit breaker inside the house and make sure no electric power is flowing to the unit before reaching inside it.
The easiest way to clean it out is to remove the side access cover. It doesn’t have to be squeaky clean inside, but remove as much debris as possible by hand. Using the tip of a knife, gently separate any fins that have been bent together to allow airflow through them. Don’t try to straighten them too much, or they may break off.
Make sure all the screws are tight when you replace the side access cover. If they are loose, air can leak in through the gap and not go through the coils. Check the tightness of the screws twice a year.
It’s equally important to have adequate airflow through the cooling coils in the indoor blower unit. Remove the access panel over the indoor coils and blower. Use the brush attachment on a vacuum cleaner to remove the dust. Use a damp rag to wipe dirt off any stubborn areas.
If the blower area is very dirty, install a higher-quality filter for better efficiency. When the air conditioner is running, check for leaky duct joints, and seal them with aluminum or heavy-duty duct tape.
Send questions to Energy Q&A, South Carolina Living, 808 Knox Abbott Drive, Cayce, SC 29033, email energyqa@scliving.coop or fax (803) 739-3041.