Air Filters Are Classified by the Size of Particles They Handle: What Does That Mean to You?

Air Filters Are Classified by the Size of Particles They Handle: What Does That Mean to You?Finding the best air filters to suit household needs can be confusing, given the array of products available. Flat filters or pleated ones, which are best? What exactly do those efficiency ratings mean in terms of healthy indoor air? The key to choosing the best air filters is in those efficiency ratings – known as MERV ratings.

MERV stands for Minimum Efficiency Reporting Value, and these ratings classify filters by their capacity to capture particles from the air. MERV ratings specify the size of the particles each filter is capable of trapping, with higher ratings signifying greater efficiency in trapping smaller particles. Here is a simple breakdown of what those ratings mean to you:

MERV 1 to 4 – Air filters with ratings in this range are typically disposable flat, or panel types. These very basic filters have a medium efficiency in trapping large airborne particles, such as dust, dust mites, pollen and carpet fibers.

MERV 5 to 8 – Filters in this ratings range may be flat panel or pleated and can capture smaller particles that include mold spores, hair spray and cement dust.

MERV 9 to 12 –  Filters in this range collect fine particles, such as humidifier dust, lead dust and auto emissions.

MERV 13-16 – This range indicates filters designed to capture even smaller particles, including bacteria and tobacco smoke.

MERV 17-20 – Used in hospitals and industrial applications, these filters remove the smallest contaminants, such as viruses and all combustion smoke.

A factor to keep in mind as you choose air filters for your home is that the higher the MERV rating, the more airflow will be restricted. For the typical home, ratings of 9-12 are generally best, offering air quality improvement without excessive airflow restriction. However, if you’re currently using a lower rated filter, it is important to check with your HVAC service tech before upgrading to ensure that higher rated ones are appropriate for your system.

For more information on choosing the best air filters, please contact Aladdin Heating & Cooling. We’ve been serving customers in Farmington, Southfield, Oak Park and throughout Southeast Michigan for over 50 years.

Our goal is to help educate our customers in Detroit, Michigan about energy and home comfort issues (specific to HVAC systems).  For more information about air filters and other HVAC topics, download our free Home Comfort Resource guide.

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