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 Calgary area homeowner's can do to ensure efficient functionality of their air conditioning and heating system between their scheduled 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 crucial to the proper performance of your HVAC system, in addition to 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 a tough thing to do for most Calgary homeowners, but there are usually two hurdles to actually accomplishing this task:

  1. Knowing 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 recommended guideline on the packaging. It may instruct "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you'll see that some are engineered to only last a month, while other manufacturers (like Honeywell) have released media air cleaners with filters meant to be changed once every 6-12 months. The standard seems to be once every few 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 contribute or cause damage to costly equipment, like your compressor, so it's recommended to change it out more often than to let it go. 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 adding a reminder for yourself in your phone or on a calendar. Also be aware that your filter manufacturer sometimes has a different recommendation from your HVAC equipment manufacturer.

Determining how often to change your air filters can depend on several factors:

  • Which air filter your system requires
  • The collective air quality of your Calgary 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 OEM specs basically tell you to change them every 1 or 2 months, which is actually 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 regularly than OEM specifications. On the other hand, if you're in a less populated area, own a less 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 we call out our beloved 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 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
  • 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

Service Experts Heating & Air Conditioning offers a simple solution; 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 Calgary 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 people know how to replace the air filter in their system, but some homes have an extra filter in the return vent. Whether you have one or not is dependent on which HVAC system you have. Your HVAC is made to handle a set amount of pressure in your home, and the more filters you have the harder 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. Locate 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 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.
Crazy as it may seem, filters can really alter your home's airflow, which is why we recommend asking the manufacturer. A top tier HEPA filter that is designed to catch finer debris will obstruct airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you should verify that your HVAC system was made to handle it. Otherwise, you may experience uneven heating and cooling efficiency in your home, and unit parts may die off much faster than normal.
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