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

February 26, 2015

Want the short answer? See our FAQ on "How often to change the air filter".  

Sometimes we’re asked what is the most important thing that Charlotte area homeowner's can do to maintain their air conditioning and heating system between their regular tune-ups? That’s an easy one; 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 Charlotte homeowners, but there are often two obstacles to actually completing this job:
  1. Determining just how often to change 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 say "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 industry standard seems to be once every 3 months for most higher quality filters, but we have a rule of thumb that we suggest our customers to go by. If it's dirty, change it! A dirty air filter can contribute or cause damage to costly components, like your compressor, so it's recommended to change it out more often than neglect it. If you want to stick to the manufacturer's recommended limit, we suggest scribbling the date on the filter when you swap it out, and setting a reminder for yourself in your phone or on a calendar. Also be aware that your filter manufacturer sometimes has a different recommendation from your HVAC system manufacturer.

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

  • The type of air filter you are using
  • The collective air quality of your Charlotte area home
  • Pets – Birds, cats, dogs, hamsters (do you have one?), etc.
  • Occupancy of the home
  • The level of air pollution and construction around the home

For your standard 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. Still, general guidelines are not applicable to all. If you have to endure 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 less populated area, own a infrequently occupied home (like a vacation home) or an area with few automobiles and trucks, changing your air filter every 12-months may be quite sufficient. Why do we call out our beloved pets? They have a tendency to shed, which can clog your air filter in no time, just like a vacuum. Obviously, the air filter is just doing its job by containing pet hair and dander, but exceptionally dirty filters can cause diminished 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

Komfort Air Service Experts offers a simple solution; 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 Charlotte 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 equipment, but some homes have an extra filter in the return vent. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your unit is designed to handle a set amount of pressure in your 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. Learning 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 remove from the wall.
  3. Inspect for a filter. If one is inside, pull it out and write down 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.
Amazing as it may seem, filters can really alter your home's airflow, which is why we recommend asking the manufacturer. A top tier HEPA filter that is designed to catch tinier dust 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 could experience lowered heating and cooling efficiency in your home, and HVAC parts may break down much faster than otherwise.