How To Tell The Difference Between Air Filters

If your home is more dusty than usual or you feel the air quality isn’t as good as it used to be, you may need to replace the air filter on your HVAC system. But how do you know whether you had a good quality air filter in the first place, or what you should replace it with?

Let’s take a look at some terms surrounding air filters so we can all understand the product better, and then we’ll look at the three main types of filters and how they help you.

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Rating Systems


The Minimum Efficiency Reporting Value (MERV) was developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. The higher the number the finer the filtration, with top performers usually having a MERV higher than 10. Air filters with higher MERV ratings not only trap more pollutants, but they’ll also need to be changed less often – which translates to less work and lower costs for you.


The Microparticle Performance Rating (MPR) was developed by 3M. It rates the filters on the ability to capture airborne particles smaller than 1 micron. The best filters have an MPR between 1500-1900.


The Filter Performance Rating (FPR) was developed by Home Depot. It rates filters on a scale of 1-10, with higher numbers being better.

Jeremy Salzbrun inspecting

Types Of Air Filters

HEPA Filters

A High-Efficiency Particulate-Arresting (HEPA) filter uses an electrical charge to help trap particles. With some of the highest MERVs available, HEPA filters remove up to 85% of pollutants, including dust and pollen. These filters are especially helpful for those with asthma, allergies or chronic lung diseases. HEPA filters can be changed about once per year.

Pleated Filters

Pleated filters are made from a polyester-blend fabric or folded sheets of cotton. They typically trap about 45% of air pollutants in your home. Pleated filters do tend to clog more often than other filters, which can break the limit switch on your HVAC system, preventing it from turning on. That means they need to be replaced more often, probably every 2-3 months depending on your household.

Fiberglass Filters

Fiberglass air filters use thin, flat panels to trap particles. Fiberglass filters trap about 10% of pollutants. Fiberglass air filters are traditionally made to protect your HVAC system, not reduce trap dirt and other contaminants.  Fiberglass filters should also be replaced every 2-3 months depending on your household.