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  • All American Inspections

The Importance of Checking Your Air Filters Regularly

Updated: Oct 22, 2021

Air filters seem to be an often forgotten but very important part of the HVAC unit. Many HVAC units could last longer or have less problems if this simple part of the unit was given more attention. This is also something that most people can do on their own and does not require a technician to come out and replace. It’s important to change your air filters regularly. We always recommend marking your calendar to look at them each month and replace them as needed. Each home will be different as to when a filter will need to be replaced. Some factors that effect this are the size of the home, pets and the quality of the filter you purchase.

Filters catch pollen and dust that would circulate through your home and lower indoor air quality. They also provide a first line of defense against larger objects such as bits of loose insulation being pulled into the system where they could cause damage or present a fire risk. However, if you don’t change your air filter regularly, you can end up with costly problems. Clogged air filters are the number one cause of HVAC system failure.

All the air handled by the HVAC system passes through the air filter at one point or another. As the filter catches more and more of the natural particulate pollution of your home (dust, mold / fugal spores, pet dander, fabric fibers, etc.) the fine mesh that air passes become denser. If you don’t change your air filter regularly, air can’t pass through as readily.


  • The blower fan in the HVAC system must work harder to push air. When it’s working harder, it’s drawing more energy, leading to higher bills. It’s also more likely to wear out from the strain.

  • The difficulty in moving air means that your living areas may not get all the air they need. This means poor home comfort for you, and the temperature sensors which regulate when the HVAC system turns on and off might not ever register the temperature needed to signal the system to power down. That’s another source of expense, which puts more strain on the fan motor.

  • Because the heated or cooled air can’t travel out of the furnace, heat pump, or air conditioner as easily, the system runs the risk of overheating or freezing up. You’ll be paying the same amount of energy or using the same amount of gas or oil, but there will be no commensurate change in indoor temperature.

  • The additional material on the air filter itself can provide a space for moisture to gather, encouraging the growth of mold or bacteria colonies. Not only do these form an even stronger barrier to circulating air, but if they colonize the wrong side of the filter, they can begin to introduce more pollutants and allergens into the indoor air. And if they get into the HVAC system and form colonies there, it could spell a lot of trouble for the entire system.

  • Because air doesn’t circulate as quickly, particulates can settle in ducts and on household surfaces when they’d usually be carried into the system and filtered. It’s a lot simpler to change your air filter than it is to schedule a duct cleaning, but dirty ducts can result in an ongoing drain to your system efficiency and a long-term source of pollutants in your air supply.


It’s best to change your air filter every month or two, especially if you have pets or live in a high-pollen area. Air filters are generally inexpensive, and changing your air filter is a simple task that doesn’t require a professional hand. In most cases, you should simply be able to slide the old filter out and slide a new one in.

Check your unit’s documentation to determine what size of filter you need, and what minimum efficiency reporting value (MERV) range the furnace should fall into. A high MERV filter with a very tight mesh may be too much for some units, resulting in a situation a lot like a clogged air filter, even just after you’ve changed it.

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