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

February 26, 2015

Need the short answer? See our FAQ on "How often to change the air filter".  

Every once in a while we’re asked what is the best thing that Raleigh area homeowner's can do to maintain their air conditioning and heating system between their scheduled tune-ups? That’s an easy one; remember to change the heating and air conditioning air filter. Changing furnace and return air filters is critical to the ideal operation of your HVAC system, as well as your home's air quality. Research suggests that indoor air pollution is among 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 difficult for most Raleigh homeowners, but there are typically two challenges to actually getting it done:
  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 recommended guideline on the box or plastic. It may read "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you'll notice that some are engineered to only last one month, while other manufacturers (like Honeywell) have released 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 customers to go by. If the filter is dirty, change it! A dirty air filter can add or cause damage to pricey components, like your compressor, so it's best to change it out more often than to let it go. If you want to listen to the manufacturer's recommended limit, we suggest writing the date on the filter when you swap it out, and adding a reminder for yourself in your phone or on a calendar. Also note that your filter manufacturer may have a different recommendation from your HVAC system manufacturer.

Deciding how often to change your air filters hinges on several factors:

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

For your typical 1"-3" air filters, the manufacturer specs basically tell you to change them every 30-60 days, which is in fact a great rule of thumb. Still, generalities may not be suitable for your specific needs. If you put up with light to moderate allergies, you may need to upgrade the air filter or change them even more regularly than OEM specifications. On the other hand, if you're in a remote area, own a less occupied home (like a vacation home) or an area with little auto traffic, annual replacement of your air filter may be quite sufficient. Why should you factor in your pets? They have a tendency to shed, which can clog your air filter quick. Clearly, the air filter is just doing its job by capturing pet hair and dander, but exceptionally dirty filters can cause seriously reduced HVAC performance.

In summary:

  • Vacation home or single occupant homes without pets or allergies: Change 6-12 months
  • Common suburban home without pets: Change every 90 days
  • Got a cat or dog: 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

Service Experts Heating & Air Conditioning offers a simple solution; 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. But wait… there’s more, your email subscription preferences let’s you set a reminder to change your Raleigh 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 of you know how to replace the air filter in their system, but some residences have an extra filter in the return ducts. Whether you have one or not is dependent on what your unit's manufacturer recommends. Your system is engineered to handle a maximum amount of pressure in your home, and the more filters you have the more the blower motor works, which can shorten the lifespan of your system if it isn't designed for it. Learning whether you have a return filter and replacing it is easy:

  1. Go to 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 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 referring to the manufacturer. A higher quality HEPA filter that is designed to catch tinier dust will restrict 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 might experience lowered heating and cooling efficiency in your home, and system parts may die off much faster than the standard.
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