MERV Furnace Filters: What Are the Benefits?

When shopping for a new furnace filter, you may have seen a number that refers to the filter’s MERV rating. MERV stands for Minimum Efficiency Reporting Value and is a number system that tells you the efficiency of an air filter. It refers to the number of air particles it can trap, size, and type. Using the MERV rating system, you can make an informed decision on the air filter that will be best for your home.

The MERV rating on a furnace filter represents the lowest possible performance, so you can be confident that this is the worst it will perform, with the potential to do more and better. While it is beneficial for everyone to be aware of their filter’s efficiency, it is even more important for people with pets, allergies, and chronic illness to choose a good MERV rating to create a clean air environment in their home or workplace.

The MERV Rating System

The MERV Rating System works by comparing a filter’s efficiency to the particle size that it can trap. Filters with high MERV ratings are able to trap most air particles of all sizes, while filters with lower MERV ratings can only trap larger air particles.

Although MERV ratings can go down to 1, furnace filters with MERV ratings between 6 and 8 are considered the bare minimum for residences and workplaces. Filters in this range will protect your HVAC system but are not overactive in trapping particles so as to restrict airflow. Filters with a MERV rating of 8-10 are considered an affordable middle-ground option for residential homes, while filters with a MERV rating of 11-13 are more effective, especially for homes with pets, allergies, or chronic illnesses like Asthma.

Filters with MERV ratings above 13 are not recommended for residential use. Although these air filters are highly effective at capturing air particles of all sizes, they require a larger HVAC system and can severely restrict airflow in a building. As a result, they are reserved for places such as medical facilities that require maximum air sanitation.

The Benefits of Each MERV Rating

Like many product rating systems, a middle-ground option is best for most situations, but there are times when the higher and lower extremes are useful. Let’s take a look at what each rating is good for:

MERV 1-4:
These are one of the cheaper options for MERV air filters. They trap larger particles such as dust mites, standing dust, pollen, and carpet fibers and are most often used in window air conditioning units.

MERV 5-8:
These are considered the bare minimum for residences and are the cheapest option for a MERV air filter. In addition to larger particles, they are able to capture hair spray particles, cement dust, and mold spores. MERV 8 is the most common rating and has 90% efficiency on particles that are 3 to 10 micrometers in size. If you do not have pets, allergies, or chronic illness, you can likely get a MERV furnace filter in this range and be comfortable.

MERV 9-13:
Although these air filters are more expensive than ones with a lower rating, they offer better air quality protection. They can trap nearly all large particles and extend down to particles in the 1 to 3-micrometer range. If you have pets, allergies, or chronic illness, these air filters will provide adequate protection. MERV 13 is considered the highest rating for residential use and the best overall.

MERV 14-16:
Air filters with a MERV rating in this range are not recommended for residential use and are the most expensive option. They can capture particles down to 0.3 micrometers inside, which include airborne bacteria, pollutants released by sneezing, and most tobacco smoke. These air filters require a more extensive HVAC system and are most often used in places like medical facilities and smoking lounges where air quality is more important than average.

For most situations, a MERV rating between 8 and 13 is more than adequate to obtain a clean air environment. You will want to err on the higher end of that range if you have pets, allergies, chronic illness, or anything else impacted by air quality. The MERV rating system gives you a sneak peek at the size, amount and type of particles it will eliminate from the air, so you can rest assured knowing you are breathing clean air.