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

February 26, 2015

Every once in a while we’re asked what is the number one thing that Kitchener area homeowner's can do to ensure efficient functionality of 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. Buying new furnace and return air filters is extremely important to the proper performance of your HVAC system, not to mention your home's air quality. Studies show 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 all that hard for most Kitchener homeowners, but there are usually two obstacles to actually completing this job:

  1. Understanding 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 printed "expiration" date on the wrapping. It may read "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you should 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 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 readers to go by. If it's dirty, change it! A dirty air filter can contribute or cause damage to expensive equipment, like your compressor, so it's better to change it out more often than neglect it. If you want to stick to 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 might have a different recommendation from your HVAC system manufacturer.

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

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

For the common 1"-3" air filters, the OEM specs basically say to change them bi-monthly, which is in fact a great rule of thumb. However, generalities may not be suitable for your specific needs. If you have to endure light to moderate allergies, you may need to upgrade the air filter or change them even more regularly than OEM specifications. On the other hand, if you're in a remote area, own a infrequently occupied home (like a vacation home) or an area with little auto traffic, annual replacement of your air filter may be quite sufficient. Why do pets matter so much? They have a tendency to shed, which can clog your air filter in no time, just like a vacuum. Obviously, the air filter is just doing its job by containing pet hair and dander, but extremely dirty filters can cause seriously reduced 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. 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 Kitchener 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 people know how to replace the air filter in their unit, but some homes have an extra filter in the return ducts. Whether you have one or not is dependent on which HVAC system you have. Your HVAC is made to handle a certain amount of pressure in your house, and the more filters you have the more the blower motor works, which can shorten the lifespan 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. Locate 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 note 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 greatly affect your home's airflow, which is why we recommend referring to the manufacturer. A top tier HEPA filter that is designed to catch tinier dust 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 made to handle it. Otherwise, you could experience reduced heating and cooling efficiency in your home, and unit parts may die off much faster than normal.
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