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

February 26, 2015

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

Sometimes we’re asked what is the best thing that Kansas City area homeowner's can do to ensure efficient functionality of their air conditioning and heating system between their seasonal tune-ups? It's a simple question with a simple answer; remember to change the heating and air conditioning air filter. Buying new furnace and return air filters is critical to the ideal operation of your HVAC system, as well as 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 difficult for most Kansas City homeowners, but there are typically two obstacles to actually accomplishing this task:

Determining just how often to swap out your furnace or air conditioner filter.
Changing them when you’re suppose to.

When To Change Your Air Filters

Most filters have a timeline printed on the box or plastic. 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 designed to only last one month, while other manufacturers (like Honeywell) have produced media air cleaners with filters meant to be changed once every 6-12 months. The standard seems to be once every 3 months for most higher quality filters, but we have a rule of thumb that we tell our friends, and family to go by. If the filter is dirty, change it! A dirty air filter can add or cause damage to costly parts, like your compressor, so it's better to change it out more often than neglect it. 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. Also note that your filter manufacturer may have a different recommendation from your HVAC system manufacturer.

Choosing 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 Kansas City area home
Pets – Dogs, cats, etc.
Occupancy of the home
How much construction is taking place in the neighborhood around your home

For your typical 1"-3" air filters, the manufacturer specs basically say to change them bi-monthly, which is in fact a great rule of thumb. Still, general guidelines are not applicable to all. If you have to endure light to moderate allergies, you might require an upgraded air filter or change them even more often than OEM specifications. On the other hand, if you're in a low population area, own a seldom occupied home (like a vacation home) or an area with few automobiles and trucks, 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. Clearly, the air filter is just doing its job by trapping pet hair and dander, but extremely 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
Average 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 great to receive discounts on service, tips and other helpful information directly to your email. In addition, your email subscription preferences let’s you set a reminder to change your Kansas City 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 you know how to replace the air filter in their equipment, but some homes have another filter in the return vent. Whether you have one or not is dependent on which HVAC system you have. Your system is engineered to handle a certain amount of pressure in your home, and the more filters you have the harder the blower motor works, which can shorten the life expectancy 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.
Look for a filter. If one is there, pull it out and write down 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 dramatically alter your home's airflow, which is why we recommend checking in with the manufacturer. A more expensive HEPA filter that is designed to catch smaller debris will restrict airflow more than a cheaper filter. With restricted airflow comes greater pressure on your system, so you need to verify that your HVAC system was made to handle it. Otherwise, you might experience reduced heating and cooling efficiency in your home, and unit parts may break down much faster than normal.

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