When Should I Change My Furnace's Air Filter?

February 26, 2015

Occassionally we’re asked what is the best thing that San Antonio area homeowner's can do to protect their air conditioning and heating system between their seasonal PLUS Maintenance Tune-ups? It's a simple question with a simple answer; 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, in addition to your home's air quality. Research suggests that indoor air pollution is one of 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 difficult for most San Antonio homeowners, but there are usually two challenges to actually accomplishing this task:

  1. Understanding 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 recommended guideline on the wrapping. It may read "Lasts up to 3 months" or "Change filter every 90 days". Check out the filters at the store and you'll see that some are meant 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 norm seems to be once every 3 months for most higher quality filters, but we have a rule of thumb that we tell our customers to go by. If the filter is dirty, change it! A dirty air filter can exacerbate or cause damage to pricey components, like your compressor, so it's better to change it out more often than not. If you want to follow the manufacturer's recommended limit, we suggest scribbling the date on the filter when you swap it out, and adding a reminder for yourself in your phone or on a calendar. Keep in mind that your filter manufacturer may have a different recommendation from your HVAC system 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 San Antonio area home
  • Pets – Birds, cats, dogs, hamsters (do you have one?), etc.
  • Number of people in the home
  • General air pollution in the San Antonio area or construction taking place nearby

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. But generalities may not be suitable for your specific needs. If you have to tolerate 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 infrequently occupied home (like a vacation home) or an area with little auto traffic, replacing your air filters each year may be quite sufficient. Why do pets matter so much? They have a tendency to shed, which can clog your air filter fast. Clearly, 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
  • Average suburban home without pets: Change every 90 days
  • House with a pet: Change every 60 days
  • Multiple pets or have allergies: Change every 30-45 days

How To Remember To Change Air Filters

Here’s an easy way to stay on top of this; 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. But wait… there’s more, 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 people know how to replace the air filter in their unit, but some residences have an additional filter in the return vent. Whether you have one or not is dependent on which HVAC system you have. Your unit is made to handle a maximum amount of pressure in your house, and the more filters you have the fiercer 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 a piece of cake:

  1. Go to your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to take off the wall.
  3. Inspect for a filter. If one is in place, pull it out and record 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.
Crazy as it may seem, filters can greatly affect your home's airflow, which is why we recommend asking the manufacturer. A higher quality HEPA filter that is designed to catch finer debris will restrict airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you should verify that your HVAC system was engineered to handle it. Otherwise, you could experience reduced heating and cooling efficiency in your home, and system parts may wear out much faster than the standard.

 

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