How Often Should I Replace My Air Filter?

dirty hvac air filter

Replacing the filter in a central air system is an important part of maintenance as it keeps the indoor air clean, and the nice thing is that you can do it yourself. As for the frequency, that depends on a few factors.

Two Types of Air Filters

Different types of air filters have different MERV ratings. MERV stands for Minimum Efficiency Reporting Value, and it rates the effectiveness of filters on a scale from 1 to 16. In short, the higher the rating is, the more particles, as well as the finer particles, the filters can trap.

Generally, homeowners only need to consider two types of filters:

  • Fiberglass air filters

  • Pleated air filters

Fiberglass filters have a MERV rating between 1 and 4 and can trap large particles of dust and dirt but not, for example, allergens. These "throwaway filters" must be replaced every 30 days before they start to compromise the airflow.

Pleated filters have a MERV rating ranging from 5 to 8 and can trap much more thanks to the greater surface area that the pleats, or folds, create. These should be replaced between 60 and 90 days.

Air Quality

Replace your filters with more frequency if you have pets, live with someone who smokes, or other external factors are compromising the air you breathe. You should also replace the filters sooner if someone in your home suffers from allergies or a respiratory condition. To filter out cigarette smoke, you could choose a filter with a MERV rating between 9 and 12, such as a rigid cell filter.

Bottom line: Set a reminder on your phone to swap out your filter every 30 to 90 days. This will go a long way toward improving HVAC performance and maintaining clean indoor air. For all of your heating and cooling needs, contact (256) 304-8883.

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