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 best thing that Richmond area homeowner's can do to secure their air conditioning and heating system between their scheduled tune-ups? Our advice is simple; remember to change the heating and air conditioning air filter. Replacing furnace and return air filters is critical to the proper performance of your HVAC system, plus your home's air quality. Did you know indoor air pollution is among 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 difficult for most Richmond homeowners, but there are typically two challenges to actually accomplishing this task:
  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 box or plastic. It may say "Lasts up to 3 months" or "Change filter every 90 days". Pay attention at the store and you'll see that some are designed to only last one 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 3 months for most higher quality filters, but we have a rule of thumb that we suggest our readers to go by. If the filter is dirty, change it! A dirty air filter can add or cause damage to costly equipment, like your compressor, so it's best to change it out more often than neglect it. If you want to listen to the manufacturer's recommended limit, we suggest scribbling the date on the filter when you swap it out, and setting a reminder for yourself in your phone or on a calendar. Keep in mind that your filter manufacturer might have a different recommendation from your HVAC system manufacturer.

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

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

For the common 1"-3" air filters, the OEM specs basically suggest to change them bi-monthly, which is actually a great rule of thumb. But general rules aren't always for everybody. If you have to tolerate light to moderate allergies, you might need to upgrade your air filter or change them even more regularly than OEM specifications. On the other hand, if you're in a less populated area, own a less occupied home (like a vacation home) or an area with little auto traffic, replacing your air filters each year may be quite sufficient. Why do we call out our beloved pets? They have a tendency to shed, which can clog your air filter in no time, just like a vacuum. Clearly, the air filter is just doing its job by containing pet hair and dander, but exceptionally dirty filters can cause weak HVAC performance.

In summary:

  • Infrequently occupied home or single occupant homes without pets or allergies: Change 6-12 months
  • Typical suburban home without pets: Change every 90 days
  • Add a dog or cat: Change every 60 days
  • Multiple 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 great to receive discounts on service, tips and other helpful information directly to your email. In addition, your email subscription preferences let’s you set a reminder to change your Richmond 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 us know how to replace the air filter in their unit, but some homes have an extra filter in the return vent. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your system is engineered to handle a maximum amount of pressure in your house, and the more filters you have the more 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 simple:

  1. Find your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to take off the wall.
  3. Look for a filter. If one is inside, pull it out and write down 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.
Amazing as it may seem, filters can dramatically 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 particles will restrict airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you need to verify that your HVAC system was built to handle it. Otherwise, you might experience lowered heating and cooling efficiency in your home, and HVAC parts may die off much faster than otherwise.
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