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

February 26, 2015

Looking for the quick answer? Check out our FAQ on "How often to change the air filter".  

Sometimes we’re asked what is the number one thing that Charleston area homeowner's can do to ensure efficient functionality of their air conditioning and heating system between their seasonal tune-ups? Our advice is simple; remember to change the heating and air conditioning air filter. Changing furnace and return air filters is extremely important to the ideal operation of your HVAC system, in addition to your home's air quality. Research suggests that indoor air pollution is one of the top five environmental health risks? We know it's the last thing on your mind, but this is really important stuff. Changing the air filters is not all that hard for most Charleston homeowners, but there are often two obstacles to actually getting it done:
  1. Determining just how often to swap out your furnace or air conditioner filter.
  2. Remembering to change air filters when needed.

When To Change Your Air Filters

Most filters have a timeline printed on the wrapping. It may say "Lasts up to 3 months" or "Change filter every 90 days". Pay attention at the store and you'll notice that some are designed to only last one month, while other manufacturers (like Honeywell) have produced media air cleaners with filters meant to be changed once every 6-12 months. The standard seems to be once every 3 months for most higher quality filters, but we have a rule of thumb that we tell our readers to go by. If the filter is dirty, change it! A dirty air filter can add or cause damage to expensive equipment, like your compressor, so it's best to change it out more often than neglect it. If you want to stick to the manufacturer's recommended limit, we suggest writing 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 may have a different recommendation from your HVAC system manufacturer.

Deciding how often to change your air filters relies upon several factors:

  • The type of air filter you are using
  • The entire air quality of your Charleston area home
  • Pets – Dogs, cats, etc.
  • Occupancy of the home
  • How much construction is taking place in the neighborhood around your home

For your typical 1"-3" air filters, the OEM specs basically tell you to change them bi-monthly, which is really a great rule of thumb. But general guidelines are not applicable to all. If you suffer from light to moderate allergies, you might require an upgraded air filter or change them even more regularly than OEM specifications. On the other hand, if you're in a remote area, own a seldom occupied home (like a vacation home) or an area with few automobiles and trucks, annual replacement of your air filter may be quite sufficient. Why do we call out our beloved pets? 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 weak HVAC performance.

In summary:

  • Seldom used home or single occupant homes without pets or allergies: Change 6-12 months
  • Typical suburban home without pets: Change every 90 days
  • Got a cat or dog: Change every 60 days
  • Several pets or have allergies: Change every 30-45 days

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

It's simple; sign up for the Service Experts Email Club. This is a convenient way to get money-saving discounts and other helpful information on your smartphone, tablet or desktop. Also, your email subscription preferences let’s you set a reminder to change your Charleston area home's air filter every 30, 60, 90, 120 or 365 days, or the date of your choosing.

How to replace your return air filter

Most people know how to replace the air filter in their system, but some houses have an additional filter in the return ductwork. Whether you have one or not is dependent on what your unit's manufacturer recommends. Your system is engineered to handle a certain amount of pressure in your home, and the more filters you have the harder the blower motor works, which can decrease the life of your system if it isn't designed for it. Finding out whether you have a return filter and replacing it is easy:

  1. Find your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to remove from the wall.
  3. Look for a filter. If one is there, 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.
Crazy as it may seem, filters can greatly alter your home's airflow, which is why we recommend checking in with the manufacturer. A higher quality HEPA filter that is designed to catch tinier dust will reduce airflow more than a cheaper filter. With restricted airflow comes greater pressure on your system, so you ought to verify that your HVAC system was engineered to handle it. Otherwise, you may experience lowered heating and cooling efficiency in your home, and HVAC parts may die off much faster than otherwise.
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