How to Understand HVAC Air Filter Ratings

Air filters remove particulates and similar pollutants from your indoor air while helping to maintain the internal airflow your cooling equipment needs to work properly. Regular filter changes are necessary, but you might find yourself confused by the different types of ratings assigned to filters. Here is a brief introduction to HVAC air filter ratings and what they mean.

MERV Ratings

A common rating for HVAC filters is the MERV rating. MERV stands for Minimum Efficiency Reporting Value and is an industry standard rating throughout the United States. MERV numbers indicate how effective an air filter is at trapping and holding particulates of sizes ranging from 0.3–10 microns. Even the largest of the particles in this range are still very small; human hairs, for example, average about 100 microns in width.

Standard MERV ratings range from 1–16, with higher numbers indicating better performance at removing particulates.

MERV filters rated 1–4 provide some filtration, but are the least effective. Filters with MERV 9–12 ratings usually provide the level of filtration most homes need. Higher-MERV filters of 13–16 offer excellent filtration, but may be too thick to use in many HVAC systems.

HEPA Filters

In some cases, even higher MERV ratings may be needed. HEPA (High Efficiency Particulate Air) filters range from MERV 17–20 and are able to remove almost 100 percent of the contaminants in the air.

HEPA filters are not often used in residential settings. They are more common in environments where air quality is extremely important, such as medical facilities, computer clean rooms, and some types of manufacturing plants. HEPA filters are extremely thick and require specialized mountings and an HVAC system that provides airflow that is strong enough to push air through the dense material of the filter.

Since 1969, Rinaldi’s Energy Solutions has provided top-quality air conditioning system design, installation, maintenance, and repair in Orlando and nearby Central Florida communities. Contact us today for more information on how to understand HVAC air filter ratings and how to choose a filter that fits your needs.

Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems).

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