Maintaining indoor air quality in a commercial or workplace setting is critical,  not just for comfort but also for the health and safety of customers and employees. Your HVAC system’s air filters are your first line of defense against unhealthy airborne particles that can cause discomfort, trigger respiratory disorders, and transmit illness. Therefore, understanding the differences in MERV filter ratings is critical when selecting the right commercial filter for your furnace, air conditioner, or heat pump.  In this article, we will be discussing what air filter ratings are, the differences in filter ratings, and comparing MERV 8 to MERV 13.

What Are Air Filter Ratings?

There are three air filter rating systems.  Each system has different ranges and was developed by various organizations. 

 

  1. MERV scale ranges from 1 to 20
  2. MPR values are based on diameters ranging from 0.3 to 1 micron
  3. FPR ratings have a scale of 4 to 10. 

 

The American Society of Heating, Refrigerating, and Air Conditioning Engineers created the MERV filter rating system as a domestic and worldwide industry-standard rating system. The other two methods were to separate “3M” (MPR) and “The Home Depot” (FPR) products.  This article will focus on the MERV system.

What is The MERV Rating System, and How Does it Work?

As you may have guessed, the MERV Rating is the industry’s primary rating system, both locally and globally. MERV is a rating system developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers that assesses a filter’s capacity to catch and retain particles and contaminants. Higher MERV ratings help capture and remove smaller particles.

 

The term MERV stands for Minimum Efficiency Reporting Value and is a well-accepted indicator of filter efficiency in the HVAC industry. The rating identifies how efficiently a filter removes airborne particles with diameters ranging from 0.3 to 10 microns. The standard filter ratings range from 1 to 20, with higher values indicating better effectiveness in eliminating airborne pollutants.

 

As the air flows through your HVAC system, air filters remove pollutants and particles from the air. They are frequently used to trap dust, pollen, fibers, metal pieces, hair, and other substances that can be breathed or contaminate surfaces. HVAC filters may also trap microorganisms, including viruses, bacteria, mold spores, and germs, which can spread disease or cause allergies or asthma attacks. 

merv filtration

How Are Ratings Determined

The efficiency of a filter in filtering particles of various sizes determines its rating. We’re talking about distinct-sized particles ranging from 0.3 to 10 micrometers in diameter.  To better understand, a human hair is around 50 m in length, while the smallest particles that the human eye can recognize are approximately 40 m in length.  MERV classifies in ranges of E1, E2, and E3.  Within each range are four subranges. The first range, E1, comprises particles ranging in size from 0.3 to 1.0 m. E2 particles range in size from 1.0 to 3.0 m, whereas E3 particles range from 3.0 to 10.0 m.

 

To establish the MERV rating of a filter, it goes through rigid testing, six tests per particle size.  Before and after each test, a count is taken of the total number of particles.  Once all tests are complete, the filtration results determine the rating.  The basis of the results is a percentage of the starting and ending particle counts.  The lowest proportion of the six tests is chosen as the official metric for determining a filter’s MERV grade. That is where the MERV minimum originates.

What Are the Differences In MERV Filter Ratings?

A higher MERV air filter rating indicates that an air filter is more effective at collecting finer particles. In contrast, a lower MERV rating implies that an air filter is capable of capturing bigger particles. As a result, the size of particles collected reduces as the values grow.  For more specific information on particle size and percentage of particles captured, see our MERV rating chart.

MERV Filter Ratings 1-4 

Filters with a rating of 1 -4 can capture larger particles like carpet and textile fibers, dirt particles, dust particles from spray paint and sanding, dust mites, and pollen.  Filters with a rating of 1-4 are usually less expensive and are for homes and commercial buildings with low traffic.  

MERV Filter Ratings 5 – 8

Filters with a rating of 5–8 can capture contaminants such as hair spray, cleaning and dusting aids, dust from cement, and mold spores.  Filters with a rating of 5-8 are for homes and businesses with medium traffic and businesses with paint booths.   

MERV Filter Ratings 9–12

Filters with a MERV rating of 9-12 are standard in both households and commercial environments.  These filters can capture contaminants and pollutants such as Dust from coal, lead, insecticides, vehicles’ emissions, milled flour, welding fumes, and paint pigments. In addition, filters with a rating of 9-12 are for facilities and homes that have a higher need for better air quality in homes, workplaces, and commercial buildings.

MERV Filter Ratings 13–16

Filters with a MERV rating of 13–16 generally remove contaminants when there is a high need for clean air.  These filters help remove bacteria, cooling oil, smoke, sneeze nuclei, viruses, and much more.  Filters with a rating of 13-16 are often for high-end residential, commercial buildings, businesses with high traffic volumes, where smoke is prevalent such as in a smoking lounge, hotels, hospitals, and surgery suites.

Merv Filter Ratings 17–20 

ULPA and HEPA air filters have ratings ranging from 17 to 20. These filters catch the tiniest particles, smaller than.3 microns in size.  Including things like carcinogenic substances, combustion smoke, carbon dust, and radioactive substances. ULPA and HEPA grade air filters are necessary for cleanrooms, high-risk operation rooms, and places where hazardous chemicals are in use.

merv filter ratings

Comparing MERV 8 to MERV 13

The difference between filters with a MERV 8 and MERV 13 rating comes down to two micrometers. And while that may not seem to be a huge difference, it is vital to examine how things function at the molecular level.

What appears to be a slight difference can potentially impact the outcome of life and death, which is why facilities such as hospitals and surgery centers use filters with higher MERV filter ratings. Therefore, it is critical to recognize the limits of a MERV 8 filter and the advantages of a MERV 13.

The Capabilities of MERV 8 Filters

MERV 8 filters may be a good choice for a typical household or business that is only concerned with keeping its HVAC system functioning correctly.  They outperform fiberglass filters while being economically priced. Filters with a MERV 8 rating can capture particles larger than 3 micrometers, sufficient to trap ordinary pollen, dust, and debris.  While this is good, it is not great.  In addition, MERV 8 filters do not work to keep the air in your commercial business or residence clean and free of particles such as viruses and bacteria.

The Capabilities of MERV 13 Filters

MERV 13 filters are ideal for commercial and residential settings that want and need higher air quality. Medical institutions often utilize filters with a MERV 13 rating. Filters with a rating of 13 can efficiently capture bacteria, mold spores, pet dander, smoke, vehicle fumes, viruses, and other micro allergens that are 1 millimeter or larger. This level of filtration can help in the prevention of harmful illnesses and allergic reactions. Avoiding these pollutants in your business or home air may result in significant health advantages.

MERV 8 MERV 13 comparison

Choosing the Right Commercial Filter

There are several reasons why you might consider choosing a MERV 13 or higher filter.   

 

Allergies – In a commercial setting, you must have the best interest of your staff in mind when it comes to safety and air quality.  Air filters that have a rating of MERV 13 can capture allergens, making the environment much more comfortable.   

 

Smog and construction – If you are located in an area with a lot of construction, factories, or pollution, utilizing a MERV 13 filter will keep the air inside cleaner.

 

Wildfire smoke – Regions prone to wildfires need to consider using a higher rating filter, such as a MERV 13.  These filters will filter out smoke caused by wildfires.

 

Covid Considerations – With the ongoing impact of Covid 19 and the new variants that seem to be popping up, protecting yourself, your family, and your employees is a big priority.  Using a filter that has a MERV 13 rating or higher can create a healthier environment, capturing up to 90% of harmful air particles, which include viruses and bacteria.

hvac filter construction

The Final Decision

What appears to be a minor variation can have a significant impact on air quality.  Keeping the health and safety of your staff in mind when purchasing quality filters helps to ensure your employees are at peak performance.  At Filti, our mission is to manufacture filters and filtration products that help keep your environment safe for everyone, whether at home or in your business.  We hope you found our article on the difference in MERV filter ratings and comparing MERV 8 to MERV13 helpful!  For more information on our commercial and industrial filters or to place an order, check out our commercial and industrial filters.  As always, stay safe!  

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