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

February 26, 2015

Sometimes we’re asked what is the number one thing that Saint Charles area homeowner's can do to protect their air conditioning and heating system between their regular tune-ups? Our advice is simple; remember to change the heating and air conditioning air filter. Buying new furnace and return air filters is crucial 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 Saint Charles homeowners, but there are often two obstacles to actually completing this job:

  1. Knowing just how often to change your furnace or air conditioner filter.
  2. Replacing them at the proper time.

When To Change Your Air Filters

Most filters have a recommended guideline on the wrapping. It may instruct "Lasts up to 3 months" or "Change filter every 90 days". Check out the filters at the store and you'll see that some are engineered 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 norm seems to be once every few months for most higher quality filters, but we have a rule of thumb that we recommend our friends and family to go by. If they're dirty, change them! A dirty air filter can exacerbate or cause damage to pricey components, like your compressor, so it's better to change it out more often than not. If you want to follow the manufacturer's recommended limit, we suggest scribbling 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 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 Saint Charles area home
  • Pets – Birds, cats, dogs, hamsters (do you have one?), etc.
  • Occupancy of the home
  • General air pollution in the Saint Charles area or construction taking place nearby

For your typical 1"-3" air filters, the OEM specs basically suggest to change them every 1 or 2 months, which is actually a great rule of thumb. However, generalities may not be suitable for your specific needs. If you suffer from light to moderate allergies, you might need to upgrade your air filter or change them even more often 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 where there are fewer cars around, 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 fast. Clearly, the air filter is just doing its job by containing 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
  • Typical 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 Saint Charles area home's air filter every 30, 60, 90, 120 or 365 days, or a specific date of your choice.

How to replace your return air filter

Most of us know how to replace the air filter in their system, but some residences have another filter in the return ductwork. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your unit 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 reduce the lifespan of your system if it isn't designed for it. Learning 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 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 affect your home's airflow, which is why we recommend asking the manufacturer. A top tier 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 need to verify that your HVAC system was engineered to handle it. Otherwise, you could experience lowered heating and cooling efficiency in your home, and unit parts may break down much faster than normal.
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