MERV is an abbreviation that stands for Minimum Efficiency Rating Value. It’s a standard used to rate air filters depending on their efficiency. The standard uses the numbers 1-20 to indicate how well an air filter holds dust and dirt. 

A rating of 1 shows the lowest efficiency while a rating of 20 shows the highest efficiency. How well an air filter holds dust and dirt also depends on the particle sizes. In this article we’ll take a look at Merv 8 vs Merv 11, two of the most common Merv ratings on the market today. 

Merv 8 description

Merv 8 air filters are categorized in the Merv 5-8 rating. They are good at catching small particles of between 3 and 10 micrometers in size. Such particles include dust mites, animal dander, hair spray, and mold pollen.

Air filters with a Merv rating of 8 are ideal for residences, industrial workplaces, commercial buildings, and paint booths. They are commonly found in American households where they help to eliminate the most common pollutants found in most homes. They also maximize efficiency and performance of air-conditioning systems. 

By trapping most indoor particulates, they keep those with allergies and asthma safe and prevent long-term respiratory problems. A typical Merv 8 air filter will last between 6 months and a year in residential use.

Strong sides

1. Relatively inexpensive.
2. Improve indoor air quality.
3. Easier to service.

Weak sides

1.  Need to be changed to maintain performance.
2. Diminished comfort when compared to higher-rated air filters.

Merv 11 description

Merv 11 air filters are categorized in the Merv 9-12 rating. They are a better option for residential use when compared to Merv 8. This because they are able to remove particulates 1-3 microns in size. This includes particles like auto emissions, legionella, lead dust, welding fumes, and humidifier dust. 

They are applicable where superior HVAC systems are in use. You’ll commonly find Merv 11 filters in commercial builds and hospital labs. Their ability to remove a higher percentage of contaminants makes them ideal where higher quality of indoor air is needed.

Strong sides

1. Higher efficiency in removing pollutants and particulates.
2. Improve indoor air quality.

Weak sides

1. Higher energy bills.
2. Cost more to purchase and maintain.

Overview

Air filters with the Merv 11 rating are better at removing pollutants and particles found in air when compared to Merv 8. However, Merv 8 is still a great air filtering option especially where you’re on a budget and where there aren’t any serious health concerns such as asthma and allergies. Only go for Merv 11 if you have more than one pet and where you or a family member surfers from a serious health condition.

FAQ

Does MERV 11 restrict air flow?

Merv 11 can restrict airflow if you have a very old HVAC system or haven’t replaced your air filter in a long time.

Will Merv 11 hurt my furnace?

Merv 11 can restrict airflow if you have an old HVAC system or an old air filter. This could affect the performance of your furnace.

How often do you change a MERV 11 filter?

Merv 11 filters should be changed every 6 months and Merv 8 filters every 3-4 months.