An AC unit is not a self-contained unit that is impervious to the forces of nature and therefore needs little to no maintenance. Instead, in order to affect the air temperature in your home, an AC unit must necessarily be exposed to the both the environment in your home and the environment outside. Thus, you must inspect the components of your system that are most affected by nature and make repairs as necessary.
To illustrate how important it is to stay up-to-date on your AC repairs and maintenance, consider that a dirty filter can decrease your AC efficiency by up to 15%. Furthermore, a dirty filter can restrict airflow so much that there is not enough air flowing over your evaporator coils, and thus the coils can get so cold that they freeze the water vapor in the air in your home. As layer after layer of ice builds up on your coils, the ice can completely block airflow into your home and put intense strain on your system. In order to figure out how often you should be changing out your filter, inspect it frequently, take notes on its condition, and then create a schedule that will get as much wear as possible out of your filter without drastically affecting the performance of your system.
While changing a filter is a part of AC maintenance that every homeowner should be aware of, ducts may not be on the average homeowner's radar. It is important to know that the air flowing through your ducts creates outward pressure that will slowly but surely compromise the seals between sections of ducts and create leaks. These leaks can reduce your efficiency by up to 40%. If your ducts run behind the walls of your home, then you will need to hire duct cleaners to inspect and repair your ducts as necessary.
Coils are a final component that deserve your attention. Specifically, your condenser coils, which are located outside your home, can get clogged with dust, leaves, dandelion fluff, and other yard debris. Dirty coils will consume up to 37% more energy than clean coils. Thus, you should inspect your coils regularly and clean them whenever necessary. To clean them, simply spray the coils with a coil cleaner to break up stuck-on grime and then scrub your coils clean with a stiff-bristle brush.
If you don't stay up-to-date on your AC maintenance, you will pay for it. The good news is that AC maintenance is not super complicated. As long as you know what to look for, you will know when to change your filter and clean your coils and by partnering with a duct cleaner, you can keep your AC running at its optimum level.