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

February 26, 2015

Looking for the short answer? Check out our FAQ on "How often to change the air filter".  

Every once in a while we’re asked what is the number one thing that Edmonton area homeowner's can do to secure 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. Replacing furnace and return air filters is crucial to the ideal operation 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? We know it's the last thing on your mind, but this is really important stuff. Changing the air filters is not a tough thing to do for most Edmonton homeowners, but there are often two hurdles to actually getting it done:
  1. Understanding just how often to replace 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 packaging. 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 meant 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 three months for most higher quality filters, but we have a rule of thumb that we tell our friends, and family to go by. If it's dirty, change it! A dirty air filter can add or cause damage to expensive components, 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 scribbling the date on the filter when you swap it out, and setting a reminder for yourself in your phone or on a calendar. Also note that your filter manufacturer might have a different recommendation from your HVAC system manufacturer.

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

  • Type of filter your A/C system requires
  • The overall air quality of your Edmonton area home
  • Pets – Dogs, cats, etc.
  • Occupancy of the home
  • How much construction is taking place in the neighborhood around your home

For your standard 1"-3" air filters, the manufacturers basically tell you to change them every 30-60 days, which is actually 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 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 remote area, own a seldom 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 fast. Of course, the air filter is just doing its job by capturing pet hair and dander, but extremely dirty filters can cause diminished HVAC performance.

In summary:

  • Infrequently occupied home or single occupant homes without pets or allergies: Change 6-12 months
  • Average suburban home without pets: Change every 90 days
  • House with a pet: 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. 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. In addition, your email subscription preferences let’s you set a reminder to change your Edmonton 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 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 certain 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 expectancy of your system if it isn't designed for it. Discovering whether you have a return filter and replacing it is simple:

  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. Check for a filter. If one is in place, 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.
Incredible though it may seem, filters can greatly alter your home's airflow, which is why we recommend checking in with the manufacturer. A more expensive HEPA filter that is designed to catch tinier debris will obstruct airflow more than a cheaper filter. With restricted airflow comes greater pressure on your system, so you should verify that your HVAC system was built to handle it. Otherwise, you may experience uneven heating and cooling efficiency in your home, and system parts may die off much faster than the standard.
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