The most important maintenance task to ensure the efficiency of your air conditioner is to replace or clean your filters on a routine basis. Dirty, clogged filters reduce the amount of air flow and significantly reduce system efficiency. Look for the minimum filter efficiency value, or MERV, which ranges from 1 to 12 for domestic air conditioning units; the higher the number, the better the filtration (and the more energy it will take to extract air through it, so balance air quality issues with energy costs). Ducts can lose up to 30 percent of airflow due to leaks, and window air conditioning units are notoriously difficult to seal properly.
To find leaks, you can use the old “smoke trick”. The air compressor and condenser in a central air conditioning system are usually outside the house, close to the foundation. It works best when there's around 24 inches of free space in all directions, so get rid of nearby shrubs, tall grass, leaves, and hanging branches. Federal laws require air conditioning units to be much more efficient than they were just 10 years ago.
For central air conditioning, look for the seasonal energy efficiency index, or SEER; for window units, the measurement is simply called the energy efficiency index, or EER. The standards require a SEER of 13 and an EER of 8, but devices with higher numbers will cost less to operate. Perhaps the most essential and easiest air conditioner maintenance task is to replace or clean air filters regularly. Dirty, clogged filters severely limit the efficiency of the air conditioner by decreasing system airflow.
In addition, when a filter is clogged, air can bypass the filter, allowing unfiltered air to flow throughout the HVAC system, potentially damaging the evaporator coil in the process. The air filters in central air conditioning units are usually found along the return duct, usually on the wall or ceiling, or sometimes in the air conditioner itself. You should replace the filter more often if you find that it gets dirty very quickly or if you have pollutants in the air in your house, such as pet hair or tobacco smoke. Regardless of the situation, plan to replace or clean air filters at least once every three months. However, like any other major appliance, air conditioners require routine maintenance to maximize their benefits.
Unless you're going on vacation, don't turn off the system; otherwise, the air compressor will have to work harder to cool the house later on. In addition to completing these maintenance tasks, consider having an air conditioning technician inspect your system once a year. Condensation from air conditioner coils contains bacteria that can form sludge and clog the drain pipe of the condensate tray. In the case of ducts, use aluminum tape to seal small gaps and duct putty in larger ones; in the case of window air conditioning units, place foam between the device and the window frame, gluing with adhesive tape as needed. In the case of window units, light an incense bar and hold it where the unit and window frame meet; in the case of a central air conditioner, hold the rod close to the duct connections. Another important maintenance task that will ensure that your air conditioning system is in good condition is to clean the air conditioner evaporator and condenser coils at least once a year.
Use this handy checklist to evaluate your HVAC system, then schedule an appointment for any air conditioner maintenance or repair you need before summer begins. Taking the time to clean your central air conditioner regularly will keep it running smoothly and efficiently for as long as possible.
