What does MERV rating mean on a furnace filter? Why should I care?

MERV is an abbreviation for Minimum Efficiency Reporting Value.

Your filters MERV rating tells you, on a scale of 1-16, how effectively your filter traps the small particles you don’t want to circulate through your home such as dust, pollen, mold, and other irritants. The higher the MERV rating, the more efficient the filter will be in trapping these airborne particles. Each filter’s rating represents its lowest possible performance, meaning every MERV rating answers the question, “worst case scenario, how many particles will this filter trap?”

Should I Buy Filters with the Highest MERV ratings?

The MERV rating is calculated by comparing the filter’s efficiency to the particle size it can capture. So, while higher MERV ratings are more efficient, the recommended MERV ratings for residential filters are between MERV 7 and MERV 13. Most airborne contaminants found in residential homes can be removed with an air filter within MERV 7 and MERV 13.

Furnace and air filters higher than MERV 13 are typically found in a hospital environment, where air sanitation is of the highest importance. Most air filters of MERV 7 or higher are effective at trapping dust, mold spores, tobacco smoke, pet dander, and pollen. A lot of homeowners don’t pay attention to their filter MERV rating, but if you’re a person with pets or allergies, then it will be beneficial for you to care more. Higher-rated filters are beneficial to those who are chronically ill; have respiratory conditions, or live with pets.

MERV Ratings Breakdown

MERV Ratings Chart

MERV 6-8

Furnace filters with MERV ratings between 6-8 are the cheapest ones and are considered the bare minimum of efficiency. MERV 6-8 filters protect your HVAC system, but are not considered the most effective at catching large portions of airborne particles. If anyone in your household suffers from allergies or asthma, you should consider getting a higher MERV air filter. Filters with a MERV 6 rating are more affordable and will provide the bare minimum for a home without furry pets.

MERV 8-10

These air filters are most common for use in residential homes and are still relatively affordable.  MERV 8-10 filters capture more of the large particles and at least half of the smaller particles like pollen, mold, and mildew spores. These air filters are also a more affordable option for allergy sufferers than higher MERV filters. So, if you’re looking for a high-quality furnace filter that’s not too expensive, then a MERV 8-10 filter is worth considering.

MERV 11-13

MERV 11-13 air filters are somewhat of a middle ground between the cheap ones and the more expensive ones. They are efficient at capturing nearly all of the largest particles, as well as most of the smaller ones. If you have pets, a MERV 11-13 filter will be much more effective at cleaning your indoor air. These air filters provide highly effective residential air filtration for a much healthier breathing environment.

MERV 13 air filters are considered the best overall for residential HVAC systems. Schools commonly use MERV 13 air filters to provide clean learning environments for their students and staff. It’s also worth noting that anything higher than MERV 13 is not recommended for residential use. MERV 13 air filters are highly effective at removing a higher range of particles including smoke, bacteria and even some viruses. They’re perfect for people who are prone to illness and need the cleanest, most sterile environment possible.

MERV 14 and higher

These air filters are incredibly efficient but are not recommended for residential use. They’re large, bulky, and are designed primarily for heavy duty filtration in places such as medical facilities. Air filters with MERV ratings above 13 also tend to restrict airflow because they have smaller pores to capture smaller particles. A MERV 14 or higher air filter can create more resistance in airflow than a residential HVAC system is designed to handle. This reduction in the air flow to your HVAC system can worsen the air quality in your home, as well as put too much pressure on your AC system.

What MERV Rating Should I Use for My Furnace Filter?

Furnace Filter

Before shopping around for higher efficiency air filters, it’s important to remember that your filter and your furnace must work in harmony. Filters with higher MERV ratings may remove more harmful contaminants from your home, but they can reduce the quality of the air you breathe if you select a filter with a MERV rating that’s too efficient for your HVAC system. You’ll also have to change these filters more frequently than filters with a lower MERV rating.

At Minnick’s, we provide the best heating, cooling, and air quality service available in Maryland and the surrounding area. Not sure which air filter is right for your furnace? Contact us online  or call us at (301) 605-9112  and we’ll be more than happy to help you out with any questions you may have about your HVAC system, especially your filter.

Minnick’s is an industry leader in providing Heating, Cooling, Plumbing, Insulation, Indoor Air Quality, and Whole Home Energy solutions to Montgomery County, Howard County, Prince Georges County, Anne Arundel County, Baltimore County, and Baltimore City