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".

Occassionally we’re asked what is the number one thing that Birmingham area homeowner's can do to maintain their air conditioning and heating system between their regular 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 critical to the proper performance of your HVAC system, plus your home's air quality. Research suggests that indoor air pollution is among 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 difficult for most Birmingham homeowners, but there are typically two challenges to actually getting it done:

Determining just how often to swap out your furnace or air conditioner filter.
Remembering to change air filters when needed.

When To Change Your Air Filters

Most filters have a timeline printed on the packaging. It may instruct "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you should see that some are engineered to only last a single month, while other manufacturers (like Honeywell) have released media air cleaners with filters meant to be changed once every 6-12 months. The industry standard seems to be once every few months for most higher quality filters, but we have a rule of thumb that we tell our customers to go by. If it's dirty, change it! A dirty air filter can contribute or cause damage to expensive components, like your compressor, so it's best to change it out more often than not. If you want to follow 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. Keep in mind that your filter manufacturer sometimes has a different recommendation from your HVAC system manufacturer.

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

Which air filter your system requires
The collective air quality of your Birmingham area home
Pets – Birds, cats, dogs, hamsters (do you have one?), etc.
Number of occupants in the house
The level of air pollution and construction around the home

For the common 1"-3" air filters, the OEM specs basically say to change them bi-monthly, which is really a great rule of thumb. But generalities may not be suitable for your specific needs. If you suffer from light to moderate allergies, you might need to upgrade your 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 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 do pets matter so much? They have a tendency to shed, which can clog your air filter quick. Obviously, the air filter is just doing its job by capturing pet hair and dander, but exceptionally dirty filters can cause seriously reduced HVAC performance.

In summary:

Seldom used home or single occupant homes without pets or allergies: Change 6-12 months
Common suburban home without pets: Change every 90 days
Got a cat or dog: 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 great to receive discounts on service, tips and other helpful information directly to your email. Also, your email subscription preferences let’s you set a reminder to change your Birmingham 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 equipment, but some homes have an additional filter in the return ductwork. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your HVAC is designed 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 reduce the life of your system if it isn't designed for it. Discovering whether you have a return filter and replacing it is easy:

Go to 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 in place, 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 really affect your home's airflow, which is why we recommend referring to the manufacturer. A more expensive HEPA filter that is designed to catch smaller debris will reduce 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 might experience uneven heating and cooling efficiency in your home, and system parts may wear out much faster than otherwise.

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