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

February 26, 2015

Occassionally we’re asked what is the most important thing that Houston 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. Replacing 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 in 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 difficult for most Houston homeowners, but there are typically two challenges to actually accomplishing this task:

  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 timeline printed on the packaging. It may read "Lasts up to 3 months" or "Change filter every 90 days". Check out the filters at the store and you'll see that some are meant to only last one month, while other manufacturers (like Honeywell) have produced media air cleaners with filters meant to be exchanged once every 6-12 months. The norm seems to be once every three months for most higher quality filters, but we have a rule of thumb that we tell our customers to go by. If the filter is dirty, change it! A dirty air filter can contribute 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 listen to the manufacturer's recommended limit, we suggest writing 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 unit manufacturer.

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

  • Type of filter your A/C system requires
  • The entire air quality of your Houston area home
  • Pets – Cats, dogs, birds, etc.
  • Number of occupants in the house
  • How much construction is taking place in the neighborhood around your home

For your typical 1"-3" air filters, the OEM specs basically suggest to change them every 30-60 days, which is really a great rule of thumb. But general guidelines are not applicable to all. If you put up with light to moderate allergies, you may need to upgrade the air filter or change them even more frequently 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 few automobiles and trucks, annual replacement of your air filter may be quite sufficient. Why should you factor in your pets? They have a tendency to shed, which can clog your air filter quick. Clearly, the air filter is just doing its job by containing 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
  • Typical suburban home without pets: Change every 90 days
  • Got a cat or dog: 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. This is a great to receive discounts on service, tips and other helpful information directly to your email. But wait… there’s more, your email subscription preferences let’s you set a reminder to change your Houston area home's air filter every 30, 60, 90, 120 or 365 days, or the date of your choosing.

How to replace your return air filter

Most of us know how to replace the air filter in their unit, but some homes have another filter in the return ductwork. Whether you have one or not is dependent on which HVAC system you have. Your system is engineered to handle a set amount of pressure in your house, and the more filters you have the fiercer the blower motor works, which can shorten the life of your system if it isn't designed for it. Finding out whether you have a return filter and replacing it is easy:

  1. Locate your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to remove from the wall.
  3. Check for a filter. If one is there, 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.
Crazy as it may seem, filters can dramatically alter your home's airflow, which is why we recommend asking the manufacturer. A higher quality HEPA filter that is designed to catch smaller dust will restrict airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you ought to verify that your HVAC system was made to handle it. Otherwise, you may experience reduced heating and cooling efficiency in your home, and unit parts may break down much faster than otherwise.
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