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

February 26, 2015

Every once in a while we’re asked what is the number one thing that San Antonio 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. Replacing furnace and return air filters is critical to the ideal operation of your HVAC system, plus your home's air quality. Studies show that indoor air pollution is one of 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 San Antonio homeowners, but there are often two obstacles to actually completing this job:

  1. Determining 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 printed "expiration" date on the wrapping. It may read "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you'll see that some are engineered to only last a month, while other manufacturers (like Honeywell) have created media air cleaners with filters meant to be swapped 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 readers to go by. If it's dirty, change it! A dirty air filter can add or cause damage to costly components, like your compressor, so it's best to change it out more often than neglect it. If you want to stick to the manufacturer's recommended limit, we suggest marking the date on the filter when you swap it out, and programming a reminder for yourself in your phone or on a calendar. Also note that your filter manufacturer might have a different recommendation from your HVAC unit manufacturer.

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

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

For the common 1"-3" air filters, the manufacturers basically suggest to change them every 1 or 2 months, which is actually a great rule of thumb. Still, general rules aren't always for everybody. If you have to tolerate light to moderate allergies, you might require an upgraded 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 little auto traffic, annual replacement of your air filter 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. Of course, the air filter is just doing its job by containing pet hair and dander, but tremendously 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
  • 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. 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. Also, your email subscription preferences let’s you set a reminder to change your San Antonio 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 an extra filter in the return ducts. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your system is designed to handle a maximum amount of pressure in your home, and the more filters you have the harder the blower motor works, which can reduce the lifespan of your system if it isn't designed for it. Discovering 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 take off the wall.
  3. Look for a filter. If one is inside, 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.
Amazing as it may seem, filters can really impact your home's airflow, which is why we recommend checking in with the manufacturer. A top tier HEPA filter that is designed to catch finer 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 engineered to handle it. Otherwise, you might experience lowered heating and cooling efficiency in your home, and unit parts may break down much faster than the standard.
Contact Us