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 most important thing that Miami area homeowner's can do to protect 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 crucial to the effectiveness of your HVAC system, not to mention your home's air quality. Did you know indoor air pollution is in the top five environmental health risks? We know it's the last thing on your mind, but this is really important stuff. Changing the air filters is not a tough thing to do for most Miami homeowners, but there are usually two challenges to actually completing this job:

  1. Knowing just how often to change your furnace or air conditioner filter.
  2. Changing them when you’re suppose to.

When To Change Your Air Filters

Most filters have a recommended guideline on the box or plastic. It may say "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you'll notice that some are meant to only last a month, while other manufacturers (like Honeywell) have produced media air cleaners with filters meant to be swapped once every 6-12 months. The norm 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 they're dirty, change them! A dirty air filter can contribute or cause damage to pricey components, like your compressor, so it's better to change it out more often than to let it go. If you want to follow the manufacturer's recommended limit, we suggest writing the date on the filter when you swap it out, and setting 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 equipment manufacturer.

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

  • Type of filter your A/C system requires
  • The collective air quality of your Miami area home
  • Pets – Birds, cats, dogs, hamsters (do you have one?), etc.
  • Number of occupants in the house
  • The level of air pollution and construction around the home

For the common 1"-3" air filters, the OEM specs basically suggest to change them bi-monthly, which is actually a great rule of thumb. Still, generalities may not be suitable for your specific needs. 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 where there are fewer cars around, 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:

  • Infrequently occupied home or single occupant homes without pets or allergies: Change 6-12 months
  • Typical suburban home without pets: Change every 90 days
  • House with a pet: 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

It's simple; 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. In addition, your email subscription preferences let’s you set a reminder to change your Miami 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 system, but some houses have an additional filter in the return vent. Whether you have one or not is dependent on which HVAC system you have. Your system is made to handle a certain amount of pressure in your home sweet home, and the more filters you have the fiercer the blower motor works, which can shorten the life expectancy of your system if it isn't designed for it. Finding out whether you have a return filter and replacing it is a piece of cake:

  1. Find your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to pull off the wall.
  3. Check 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 dramatically 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 dust 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 made to handle it. Otherwise, you could experience reduced heating and cooling efficiency in your home, and HVAC parts may die off much faster than the standard.
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