Your heating and cooling system has an air filter that uses fibrous or porous material to capture dirt and debris from the air. It is usually located in the return air duct compartment. If you have a washable filter, you need to clean it every 3 months (at a minimum). If you have a disposable filter, you need to replace it that often.

When you do not keep a clean air filter, there are consequences – both for your indoor air quality and for your equipment.

Air quality is affected

The air filter is designed to collect airborne contaminants from reaching your indoor air. Depending on the quality of the air filter, it will filter out undesirable particles, including:

  • Dust
  • Pet dander
  • Pollen
  • Mold
  • Smoke
  • Bacteria

Your air filter is a barrier to trap these things, but over time the filter gets full. When it becomes dirty and clogged with debris, it becomes less efficient and you start getting air that is increasingly full of dust and other contaminants. As a result, you begin having dirty air recirculated, becoming worse and worse. You’ll also notice a thicker layer of dust settling on every surface.

Energy efficiency is affected

A dirty filter restricts air flow, and this leads to a few potential issues:

  • Frequent cycling – It’s normal for your heating and cooling equipment to kick on and off during the day as it brings the interior air to the desired temperature. However, when the air filters are dirty they have to cycle more frequently to get the job done.
  • Uneven energy distribution – When airflow is restricted by a dirty filter, it can result in uneven temperatures throughout your home. Some rooms may be hard to heat/cool, while others feel too warm/cool. If you notice that, check first to see if your filter needs attention.
  • Higher energy bills – When your system is having to work harder to produce the same output, it means more energy consumed, and that means more money consumed by higher energy bills.
  • Equipment is affected

    When air filters don’t get changed, it can cause a lack of efficiency in the system output – but beyond that it can possibly lead to expensive repairs and shorten the life of your equipment.

  • Frozen coils – When air filters get really clogged and dirty, and air flow gets restricted, it can cause air build-up inside your air conditioner. That cold, uncirculated air can lead to ice forming on the coils, and your unit can freeze up.
  • Motor failure – On the other hand, the continual strain of restricted air flow can also cause a fan motor to overheat and eventually fail.