What Do MERV Ratings Mean?

Man changing air filters

Furnace filters play an important role in the function of your heating and cooling system as well as the home’s indoor air quality. Not only do they keep your home’s air clean and circulating properly, but they also protect the HVAC system from dust and dirt. As with any other appliance or product, it’s important to shop for the right furnace filter for your needs. MERV filter ratings are one element you’ll need to pay attention to as you choose the right filters for your home and HVAC system. Novak Heating and Cooling breaks down the meaning of MERV and explains how furnace filters function.

What Are MERV Filter Ratings?

If you’re shopping for a furnace filter, you’ll likely see a MERV rating on the package. Do you know what those numbers mean?

MERV stands for minimum efficiency reporting value, and it’s the standard measure of how effectively a filter can remove particulate matter from air passing through it. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) developed a method to test filter efficacy, and MERV filter ratings were derived from these tests in 1987.

HVAC air filters receive a MERV rating that corresponds with their efficiency for removing certain particle size ranges from the air supply. MERV ratings begin at 1 and extend to 16 – the higher the MERV rating, the better the filter can remove particulate matter from the air. Particle size ranges represented by a MERV rating are 3.0 to 10.0 microns, 1.0 to 3.0 microns, and 0.3 to 1.0 microns.

Determining the Right MERV Filter Ratings to Use with Your HVAC System

An air filter with an extremely high MERV rating is not always a good thing. Many homeowners assume using an air filter with ratings at the higher end of the MERV scale will offer the cleanest air quality, but that doesn’t mean this is the right air filter for your home.

These highly efficient filters generally aren’t meant for use with residential HVAC systems. To achieve high-efficiency filtration, these filters contain denser media to remove finer particles in greater volumes. An HVAC system needs a powerful fan to properly circulate air through this filter and keep the heating and cooling system running properly.

Residential HVAC systems typically aren’t powerful enough to accommodate an air filter with a MERV rating in the highest range. If you use an air filter that is rated too high for your home’s HVAC system, the dense filter media will actively restrict airflow through the heating and cooling system and the filter effectively acts much the same as a typical filter that has become clogged with debris. Using filters with the highest MERV rating in residential heating and cooling equipment increases energy consumption, causing more stress and wear to the HVAC system.

It’s important to optimize filtration by choosing high MERV air filter ratings that are compatible for use with your residential HVAC unit and your indoor air quality needs. A filter with a MERV of 8 to 13 filters are generally recommended, depending on your specific needs. Pet dander, smoking, carpeting, family members with allergies, and other factors can impact air quality and filtration needs, so be sure to take all of these into account when making your purchase.

Benefits Associated with High MERV Ratings

As long as you choose options with MERV air filter ratings that are appropriate for use with your type of heating and cooling system, using filters with higher MERV ratings can offer many bonuses for homeowners.

For people with allergies or asthma, using filters with higher MERV ratings can offer better air filtration for the home. More allergen particles are trapped by the filter and removed from living areas, decreasing exposure to particles that cause allergy and asthma symptoms.
Greater efficacy also keeps particles out of the HVAC unit, which prevents stress and wear and tear damage.
Filters with higher MERV ratings can help with odor control in the home by removing fine particles that cause odors to linger in living spaces.

Find the Right Filters with Novak Heating and Cooling

A clear understanding of MERV filter ratings allows you to choose the right options for your home. If you have questions about HVAC filters or improving indoor air quality at home, call Novak Heating and Cooling.