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 Livermore area homeowner's can do to maintain their air conditioning and heating system between their scheduled PLUS Maintenance Tune-ups? Our advice is simple; remember to change the heating and air conditioning air filter. Replacing furnace and return air filters is critical to the effectiveness of your HVAC system, plus 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 all that hard for most Livermore homeowners, but there are typically two challenges to actually accomplishing this task:

  1. Understanding just how often to replace your furnace or air conditioner filter.
  2. Remembering to change air filters when needed.

When To Change Your Air Filters

Most filters have a recommended guideline on the packaging. It may say "Lasts up to 3 months" or "Change filter every 90 days". Pay attention at the store and you should see that some are designed to only last a 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 few months for most higher quality filters, but we have a rule of thumb that we recommend our customers to go by. If it's dirty, change it! 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 listen to the manufacturer's recommended limit, we suggest marking the date on the filter when you swap it out, and setting a reminder for yourself in your phone or on a calendar. Keep in mind 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:

  • The type of air filter you are using
  • The overall air quality of your Livermore area home
  • Pets – Birds, cats, dogs, hamsters (do you have one?), etc.
  • Occupancy of the home
  • How much construction is taking place in the neighborhood around your home

For the common 1"-3" air filters, the OEM specs basically say to change them every 1 or 2 months, which is in fact a great rule of thumb. Still, generalities may not be suitable for your specific needs. If you suffer from light to moderate allergies, you may need to upgrade the air filter or change them even more often 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 do pets matter so much? 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 trapping pet hair and dander, but tremendously 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
  • 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. 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 Livermore area home's air filter every 30, 60, 90, 120 or 365 days, or any date you find most convenient.

How to replace your return air filter

Most of us know how to replace the air filter in their equipment, but some residences have an additional filter in the return vent. Whether you have one or not is dependent on what your unit's manufacturer recommends. Your unit is engineered to handle a maximum amount of pressure in your home sweet home, and the more filters you have the fiercer the blower motor works, which can reduce the life expectancy of your system if it isn't designed for it. Discovering whether you have a return filter and replacing it is easy:

  1. Find 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 in place, 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.
Incredible though it may seem, filters can dramatically alter your home's airflow, which is why we recommend referring to 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 uneven heating and cooling efficiency in your home, and HVAC parts may die off much faster than otherwise.
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