Cleaning A/C coils boosts efficiency
As the weather gets warmer and warmer, it is wise to make sure your existing central air conditioner is running as efficiently as possible to reduce your electric bills.
There are some things you can do yourself to keep your central air conditioner running as efficiently as possible. It should be noted, though, that doing some things yourself does not preclude having regular professional service calls. Technicians have special equipment and pressure gauges to check the internal components of the system, which is impossible for a homeowner to do on his or her own. Regular service calls can also extend the life of a central air conditioner.
In doing any cleaning tasks yourself, it helps to have an understanding of how an air conditioner works. It operates on a delicate balance of air flow rates over the indoor and outdoor coils and proper pressures of the refrigerant. The compressor compresses the refrigerant to make it very hot. This hot liquid is hotter than the outdoor air, so it loses heat to the outdoor air through the condenser coils.
The cooler refrigerant then goes through an evaporator, which makes it very cold. This is similar to how your skin cools off when perspiration evaporates. This cold refrigerant flows through the indoor coil. The blower moves indoor air over these cold coils, which cools your house air. At the same time, water condenses on the cold coils so the indoor air is both cooled and dehumidified.
As you can see, getting adequate air flow through the outdoor condenser coils is important for efficiency so the refrigerant will be colder when it gets indoors. It can really help efficiency to make sure weeds and shrubs have not grown too close to the outdoor unit to impede air flow. Also, don't rest rakes or other items against it, which may block air flow.
First, switch off the circuit breaker to the unit. Then remove the outdoor cabinet. Clean out any debris that has accumulated inside it, which may block the coils. You don't have to make it spotless, though. If fins have been bent over in spots, try to straighten them out enough so more air gets through.
It is important that all the screws holding the cabinet sections together are tight when you reinstall the cabinet. Even if it is clean and you do not remove the cabinet, check all the screws. If they are loose, leaks will draw air in gaps instead of through the coils as designed.
Just as the proper amount of air flow is important through the outdoor coils, it is also important through the indoor coils. With the circuit breaker still switched off, remove the side cover on the indoor unit to expose the evaporator coils and the blower. When you reinstall the cover, make sure to tighten the screws.
Quite a bit of dirt can accumulate on the indoor coils, blocking air flow and insulating them from the air. This is because the coils get damp when the air conditioner is running and dirt sticks to it. Wipe the coils and then use the brush attachment on your vacuum cleaner to clean them and the blower as well as possible.
Even though everyone has heard to change the blower filter regularly, most people don't do it. At the beginning of the cooling season, change the filter whether you think it is dirty or not. A dirty filter increases air flow resistance, which reduces efficiency. Check the joints in the ducts for any air leaks. Seal them with aluminum tape or black Gorilla duct tape.