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

February 26, 2015

Need the quick answer? Check out our FAQ on "How often to change the air filter".

Every once in a while we’re asked what is the best thing that Rochester area homeowner's can do to ensure efficient functionality of their air conditioning and heating system between their seasonal tune-ups? The answer is simple this; 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 in 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 Rochester homeowners, but there are often two hurdles to actually getting it done:

Understanding just how often to change your furnace or air conditioner filter.
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 read "Lasts up to 3 months" or "Change filter every 90 days". Pay attention 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 swapped 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 suggest our readers to go by. If it's dirty, change it! A dirty air filter can exacerbate or cause damage to expensive components, 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 might have a different recommendation from your HVAC system manufacturer.

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

Which air filter your system requires
The overall air quality of your Rochester area home
Pets – Cats, dogs, birds, etc.
Number of occupants in the house
General air pollution in the Rochester area or construction taking place nearby

For your typical 1"-3" air filters, the manufacturers basically tell you to change them every 1 or 2 months, which is really a great rule of thumb. However, general guidelines are not applicable to all. If you have to tolerate 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 quick. Naturally, the air filter is just doing its job by trapping pet hair and dander, but exceptionally dirty filters can cause weak HVAC performance.

In summary:

Vacation home or single occupant homes without pets or allergies: Change 6-12 months
Common suburban home without pets: Change every 90 days
House with a pet: 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

Here’s an easy way to stay on top of this; 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. But wait… there’s more, your email subscription preferences let’s you set a reminder to change your Rochester 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 you know how to replace the air filter in their system, but some houses have an additional filter in the return ducts. 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 expectancy of your system if it isn't designed for it. Discovering whether you have a return filter and replacing it is simple:

Find your return air vents.
Some covers have screws and some have tabs. Unscrew or pull tabs to remove from the wall.
Check for a filter. If one is inside, pull it out and note the size.
Verify the filter type is the one recommended by the manufacturer.
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 affect your home's airflow, which is why we recommend referring to the manufacturer. A higher quality HEPA filter that is designed to catch tinier debris will restrict 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 made to handle it. Otherwise, you may experience uneven heating and cooling efficiency in your home, and unit parts may break down much faster than otherwise.

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