By Gordon White
Keep your air conditioner’s coils clean, and it may thank you with cheaper electric bills and a longer lifespan. You might also get a great before-and-after pic to share with your friends, showing the transformation from dirtied coils to cleaned ones.
To keep it simple, your cooling system has two sets of coils: the evaporator and the condenser. In the HVAC dictionary, these are called heat exchangers. Heat exchangers are where the magic of home cooling happens. The evaporator captures heat from inside the house, and the condenser expels that heat outside. In other words, the heat of your home is exchanged for a cooler temperature. Clever, right?
Both the condenser and the evaporator consist of winding coils, designed to have as large of a surface area as possible. More surface area means more places for the coils to absorb/expel heat, but if the coils get too dirty, they don’t perform their job perfectly. They are not able to remove the heat from a home as much as they should. This leads to the system running longer, which increases utility costs and shortens the lifespan of the equipment. Luckily, the coils can be cleaned, resolving these issues.
An HVAC technician can look at a system’s coils and know whether they are too dirty. The coils are often so dirty that they can show the homeowner exactly how much crud has built up, including rust, corrosion, dirt, human or pet hair, and grease. This stops your system from cooling the home as much as should otherwise be possible and can reduce ventilation, leading to more discomfort and higher energy costs.
When the coils are too dirty to do their job, a technician will apply a coat of coil cleaner and spray down the machine to remove all of the extra crud. Different metals are used for the coils, so the technician will select the proper cleaner to ensure no part of the system gets damaged. This can lead to some amazing before-and-after pictures, as the difference between clean and dirty coils is evident even to an untrained eye.
Coils have a number of different configurations of their fins, which are used for transferring heat. Different types of fins, such as plate fins and spiral fins, require different methods of cleaning. Certain shapes may be easier to clean, more delicate, or more likely to be clogged with impurities. Aluminum “microchannel” coils have become more popular for lighter weight and increased surface area, but they can react with cleaning chemicals if the wrong ones are used. The right HVAC contractor will keep this all in mind when servicing your home.
Different homes and systems will have different ideal schedules for coil cleanings. Sometimes an annual cleaning is all that is needed, while other systems may need more than that if they are in an environment with a lot of pollen or dust. Other aspects, such as the filter maintenance on a system, can affect the need to clean the coils. Performing the task during regular preventative maintenance visits is good practice, as this can help keep the coils operating as well as possible.
Dirty coils can lead to an air conditioner working harder than it needs, which in turn can lead to higher energy bills, more wear and tear on a system, and thus a shorter system lifespan. Keeping the coils clean can reverse all of that, saving you money on both short-term utilities and long-term system replacement.