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

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

1. Understanding just how often to swap out 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 packaging. It may say "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you should see that some are meant to only last a month, while other manufacturers (like Honeywell) have released media air cleaners with filters meant to be swapped once every 6-12 months. The norm seems to be once every 3 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 add or cause damage to expensive parts, 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 marking the date on the filter when you swap it out, and programming a reminder for yourself in your phone or on a calendar. Also be aware that your filter manufacturer may have a different recommendation from your HVAC system manufacturer.

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

• The type of air filter you are using
• The overall air quality of your Calgary area home
• Pets – Cats, dogs, birds, etc.
• Number of occupants in the house
• General air pollution in the Calgary area or construction taking place nearby

For your standard 1"-3" air filters, the OEM specs basically tell you to change them every 30-60 days, which is in fact a great rule of thumb. However, general rules aren't always for everybody. If you put up with 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 less occupied home (like a vacation home) or an area with little auto traffic, 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 capturing 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
• 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. 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 of us know how to replace the air filter in their unit, 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 system is made to handle a certain amount of pressure in your house, and the more filters you have the fiercer the blower motor works, which can reduce the lifespan of your system if it isn't designed for it. Finding out 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 pull 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.