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

February 26, 2015

Want the short answer? Read our FAQ on "How often to change the air filter".  

Occassionally we’re asked what is the most important thing that Canada area homeowner's can do to ensure efficient functionality of their air conditioning and heating system between their regular tune-ups? That’s an easy one; remember to change the heating and air conditioning air filter. Replacing furnace and return air filters is crucial to the proper performance of your HVAC system, as well as your home's air quality. Studies show 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 all that hard for most Canada homeowners, but there are usually two hurdles to actually accomplishing this task:
  1. Determining just how often to change your furnace or air conditioner filter.
  2. Remembering to change air filters when needed.

When To Change Your Air Filters

Most filters have a printed "expiration" date on the box or plastic. It may say "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 designed to only last a single month, while other manufacturers (like Honeywell) have produced media air cleaners with filters meant to be swapped once every 6-12 months. The norm seems to be once every three months for most higher quality filters, but we have a rule of thumb that we suggest our friends, and family to go by. If the filter is dirty, change it! A dirty air filter can add or cause damage to expensive parts, like your compressor, so it's recommended to change it out more often than not. If you want to follow the manufacturer's recommended limit, we suggest writing 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 may have a different recommendation from your HVAC system manufacturer.

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

  • Type of filter your A/C system requires
  • The collective air quality of your Canada area home
  • Pets – Cats, dogs, birds, etc.
  • Number of people in the home
  • The level of air pollution and construction around the home

For your standard 1"-3" air filters, the OEM specs basically say to change them every 30-60 days, which is really a great rule of thumb. Still, generalities may not be suitable for your specific needs. If you have to tolerate light to moderate allergies, you might need to upgrade your air filter or change them even more frequently than OEM specifications. On the other hand, if you're in a less populated area, own a infrequently occupied home (like a vacation home) or an area where there are fewer cars around, 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 fast. Clearly, the air filter is just doing its job by containing pet hair and dander, but extremely dirty filters can cause diminished HVAC performance.

In summary:

  • Vacation home or single occupant homes without pets or allergies: Change 6-12 months
  • Typical suburban home without pets: Change every 90 days
  • House with a pet: 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. Also, your email subscription preferences let’s you set a reminder to change your Canada 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 homes have an additional filter in the return vent. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your unit is engineered to handle a set amount of pressure in your home sweet home, 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 a piece of cake:

  1. Go to your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to take off the wall.
  3. Inspect 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.
Crazy as it may seem, filters can greatly affect your home's airflow, which is why we recommend asking the manufacturer. A more expensive HEPA filter that is designed to catch smaller debris will obstruct airflow more than a cheaper filter. With restricted airflow comes increased pressure on your system, so you ought to verify that your HVAC system was engineered to handle it. Otherwise, you may experience reduced heating and cooling efficiency in your home, and HVAC parts may break down much faster than otherwise.
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