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

February 26, 2015

Sometimes we’re asked what is the most important thing that Champaign area homeowner's can do to protect their air conditioning and heating system between their seasonal tune-ups? It's a simple question with a simple answer; 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, not to mention your home's air quality. Research suggests that indoor air pollution is among the top five environmental health risks? You probably don’t consider it as you sit and watch TV, but this is the air you breathe day and night. Changing the air filters is not difficult for most Champaign homeowners, but there are usually two challenges to actually completing this job:

  1. Determining just how often to change 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 wrapping. It may say "Lasts up to 3 months" or "Change filter every 90 days". Check out the filters at the store and you'll notice that some are engineered to only last one month, while other manufacturers (like Honeywell) have created media air cleaners with filters meant to be exchanged once every 6-12 months. The norm 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 it's dirty, change it! A dirty air filter can add or cause damage to costly parts, like your compressor, so it's better to change it out more often than neglect it. 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 setting a reminder for yourself in your phone or on a calendar. Also be aware that your filter manufacturer might have a different recommendation from your HVAC unit manufacturer.

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

  • The type of air filter you are using
  • The entire air quality of your Champaign area home
  • Pets – Dogs, cats, etc.
  • Number of occupants in the house
  • General air pollution in the Champaign area or construction taking place nearby

For your standard 1"-3" air filters, the OEM specs basically say to change them bi-monthly, which is really a great rule of thumb. However, general guidelines are not applicable to all. If you put up with light to moderate allergies, you might require an upgraded air filter or change them even more frequently than OEM specifications. On the other hand, if you're in a low population area, own a less occupied home (like a vacation home) or an area with little auto traffic, changing your air filter every 12-months may be quite sufficient. Why should you factor in your pets? They have a tendency to shed, which can clog your air filter in no time, just like a vacuum. 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:

  • Infrequently occupied 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
  • Several pets 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. But wait… there’s more, your email subscription preferences let’s you set a reminder to change your Champaign 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 residences have an extra filter in the return vent. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your HVAC is made to handle a maximum amount of pressure in your home sweet home, and the more filters you have the more the blower motor works, which can reduce 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. Locate your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to pull off the wall.
  3. Look 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.
Amazing as it may seem, filters can really impact your home's airflow, which is why we recommend checking in with the manufacturer. A top tier HEPA filter that is designed to catch finer particles will reduce airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you ought to verify that your HVAC system was engineered to handle it. Otherwise, you could experience lowered heating and cooling efficiency in your home, and HVAC parts may die off much faster than the standard.
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