The largest appliance expense for most homeowners is their heating, ventilation and air conditioning (HVAC) system.  As with a well-maintained car, you can get the most “mileage” out of your HVAC investment by faithfully doing one simple thing:  changing your unit’s air filter regularly.

An air filter’s job is to remove airborne particles from the air in an effort to keep the air clean.  The more particles are removed from the air, the higher the air quality – and the better the environment for your lungs.  And high quality air is crucial for those who suffer from respiratory diseases such as allergies or asthma.

As simple as air filters may sound, many homeowners get confused when it comes to choosing the correct type of filter and knowing when to change them.  These answers will be different for every household, depending on a variety of factors such as how often – and how many – people occupy the home, if any of those people have respiratory challenges, if there is any construction or other projects going on that can pollute the air, and if your family has any pets.  Here are some general guidelines:

What type of air filter should I get?

  • Fiberglass – this is the most popular and inexpensive choice.  These filters are disposable and made out of layered fiberglass fibers that are covered with a metal grating.
  • Polyester and pleated – the “cousins” of fiberglass filters, these are a little more effective at catching particles and are great for stopping dust.
  • Washable – a less common option, these filters are made out of cloth and have to be washed frequently.  Pros:  you can clean and re-use the filter, saving money and not contributing to landfills.  Cons:  you have to clean the filter, and fungus can develop if the filter is not fully dry before you reinstall it.
  • High efficiency particulate air (HEPA) – considered top of the line and expensive, these filters catch very fine particles and result in the highest air quality.

How often should I change my air filter?

Now that you’ve identified the best filter for your family’s needs, how often should you change the darn thing?  Most HVAC manufacturers suggest replacing the filter every 30 to 60 days.

If you have allergies or pets, you can do one of two things:  make sure you are using the highest quality air filter or change the filters every 30 – 45 days.  If you do not have pets you might be able to extend the time to 90 days without severely lowering air quality.  If you are in a vacation home or are a single occupant without any allergies or pets, you could try changing your filter once every six months.

Once you decide on a filter changing schedule, make sure to mark it on your calendar or choose a day that will be easy to remember, such as the first day of each month.