When Should I Change My Air Conditioner's Air Filter at Home?

February 26, 2015

Occassionally we’re asked what is the most important thing that Tempe area homeowner's can do to ensure efficient functionality of their air conditioning and heating system between their seasonal tune-ups? The answer is simple this; remember to change the heating and air conditioning air filter. Buying new furnace and return air filters is extremely important to the proper performance of your HVAC system, plus your home's air quality. Did you know indoor air pollution is one of the top five environmental health risks? It’s not thought of often, but it is extremely important to consider. Changing the air filters is not a tough thing to do for most Tempe homeowners, but there are often two hurdles to actually completing this job:

  1. Determining just how often to swap out your furnace or air conditioner filter.
  2. Changing them when you’re suppose to.

When To Change Your Air Filters

Most filters have a printed "expiration" date on the box or plastic. It may say "Lasts up to 3 months" or "Change filter every 90 days". Check out the filters at the store and you should see that some are meant to only last a month, while other manufacturers (like Honeywell) have released media air cleaners with filters meant to be swapped once every 6-12 months. The industry standard seems to be once every few months for most higher quality filters, but we have a rule of thumb that we recommend our readers to go by. If the filter is dirty, change it! A dirty air filter can contribute or cause damage to expensive parts, like your compressor, so it's recommended to change it out more often than not. If you want to listen to the manufacturer's recommended limit, we suggest marking the date on the filter when you swap it out, and programming a reminder for yourself in your phone or on a calendar. Keep in mind that your filter manufacturer sometimes has a different recommendation from your HVAC equipment manufacturer.

Choosing how often to change your air filters can depend on several factors:

  • Which air filter your system requires
  • The overall air quality of your Tempe area home
  • Pets – Cats, dogs, birds, etc.
  • Occupancy of the home
  • General air pollution in the Tempe area or construction taking place nearby

For your standard 1"-3" air filters, the OEM specs basically suggest to change them bi-monthly, which is really a great rule of thumb. Still, general guidelines are not applicable to all. If you have to endure light to moderate allergies, you may need to upgrade the air filter or change them even more often than OEM specifications. On the other hand, if you're in a remote area, own a infrequently occupied home (like a vacation home) or an area with little auto traffic, annual replacement of your air filter may be quite sufficient. Why do pets matter so much? They have a tendency to shed, which can clog your air filter quick. Of course, the air filter is just doing its job by capturing pet hair and dander, but tremendously dirty filters can cause diminished HVAC performance.

In summary:

  • Infrequently occupied home or single occupant homes without pets or allergies: Change 6-12 months
  • Common suburban home without pets: Change every 90 days
  • Add a dog or cat: Change every 60 days
  • More than one pet or have allergies: Change every 30-45 days

How To Remember To Change Your Air Conditioner's Air Filters

Here’s an easy way to stay on top of this; sign up for the Service Experts Email Club. When you do, you can elect to receive (or not) great email coupons and newsletters with a lot of tips and discounts on AC repairs and tune-ups. Also, your email subscription preferences let’s you set a reminder to change your Tempe area home's air filter every 30, 60, 90, 120 or 365 days, or any date you find most convenient.

How to replace your return air filter

Most of us know how to replace the air filter in their unit, but some houses have another filter in the return vent. Whether you have one or not is dependent on what your unit's manufacturer recommends. Your unit is engineered to handle a set amount of pressure in your house, and the more filters you have the fiercer the blower motor works, which can reduce the life expectancy of your system if it isn't designed for it. Finding out whether you have a return filter and replacing it is a piece of cake:

  1. Locate your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to pull off the wall.
  3. Check for a filter. If one is inside, pull it out and record the size.
  4. Verify the filter type is the one recommended by the manufacturer.
  5. If filter is dirty, replace with the manufacturer's recommended filter of the same size and type.
Incredible though it may seem, filters can dramatically alter your home's airflow, which is why we recommend asking the manufacturer. A higher quality HEPA filter that is designed to catch smaller particles will obstruct airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you should verify that your HVAC system was engineered to handle it. Otherwise, you may experience reduced heating and cooling efficiency in your home, and unit parts may break down much faster than otherwise.
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