Everything You Need to Know About Air Conditioning Filters

Does your home's air conditioning system need a filter? If you have a new AC unit or are just new to the world of air conditioners, take a look at everything you need to know about your system, filters, and when to call for service.

Can You Use an Air Conditioner Without a Filter?

While you could use your air conditioner without a filter, you shouldn't. Air conditioner filters trap dust, allergens, pet fur/dander, debris, and other hard-to-see particles. Failure to use a filter may:

  • Decrease indoor air quality. A working filter helps to reduce indoor air pollution. The filter prevents pollutants from re-circulating around your home.
  • Result in a dirty central AC unit. Not only will a working air filter keep your home's indoor air clean, it can stop particles from reaching the central air conditioner unit.
  • Damage your AC system. Without a filter, your system is subject to excessive wear and tear—and possibly damage.

Your AC system should come with a filter installed. If you don't know where it is, ask the HVAC technician to show you the location of the filter and how to change/clean it.

Can You Use Any Filter?

Which filter should you use? There are more than a few AC filters available in home improvement stores or online. When you choose a filter, consider:

  • The size. Your AC unit requires a specific size of filter. Some filters have the size measurements marked on the outside. If yours doesn't, an HVAC technician can help you to determine the size during your next scheduled maintenance appointment.
  • The material. Common household AC filters are made from fiberglass, paper, and polyester.
  • The ability to reuse. Some homeowners may prefer to clean the filter. If you don't want to replace your filter regularly, discuss a reusable/cleanable option with the HVAC technician.

Along with these factors, you may want to explore the use of a specialized filter.

What Are Specialized Filters?

Do you have allergies, asthma, or another respiratory condition? If you (or a household member) have special respiratory needs, your AC system can help. Specialized filters that may lead to, when used correctly, improved indoor air quality include:

  • HEPA filters. High-efficiency particulate filters can remove 99.97 percent of airborne particles 0.3 microns or larger, according to the U.S. Environmental Protection Agency (EPA).
  • UV filters. These filters use ultraviolet light to eliminate some bacterial and viral particles.
  • Electrostatic filters. Electrostatic filters use a charge to attract dust and debris to the filter's material.

Even though air filters can improve air quality and help your system to work at peak performance, these AC accessories aren't substitutes for routine air conditioning services. Continue to schedule regular pre- and post-season checkups to maintain your system. If your system isn't energy efficient, the air is dirty, or filters clog quickly, contact a qualified HVAC contractor for a service call as soon as possible.