What is a MERV Rating and Why Does it Matter?

Have you ever shopped around for a new air filter? If so, you’ve probably come across MERV ratings. MERV stands for “Minimum Efficiency Reporting Value,” and it measures how effectively an air filter removes particulates from the air.

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While you may not have realized it, MERV ratings are a big part of what makes one filter different from another. And if you’re in the market for a new home air filter, it’s important to understand how they work and how they can affect your health.


What is a MERV Rating?

MERV stands for Minimum Efficiency Reporting Value. A MERV rating measures a furnace filter’s ability to remove particles from the air that passes through it.

Filters with higher MERV ratings are more effective at removing particles such as pollen, dust, and mold spores than those with lower ratings. Having the correct filter means they’re better able to keep your HVAC system running smoothly and efficiently, reducing energy costs and extending its life.

Wondering who came up with the MERV rating?

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It was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The society is a professional organization of engineers, scientists and other professionals who design and maintain heating, ventilation and air conditioning systems.


Understanding a MERV Rating

In a nutshell, MERV ratings are determined by the number of particles a filter can capture in its surface area. Therefore, the more efficient a filter is, the higher its MERV rating.

For example, a filter with a MERV rating of 1 isn’t very efficient and can only remove large particles from your air. Whereas a filter with a MERV rating of 11 would catch much smaller particles.

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Air filters range from a MERV rating of 1 to 20. You might think the highest rating is the best for your home, but you’d be wrong. Generally, the highest-rated air filters are only suitable for sterile environments like hospitals or laboratories – places that need protection from dangerous bacteria and viruses.

Residential HVAC systems are slightly different. You could use a low range filter with a MERV rating of under 8. But your home HVAC works most efficiently with an air filter with a MERV rating of between 8-12.

MERV Ratings and Their Uses

MERV Rating 1-7

MERV ratings 1-7 are effective at removing particles from the air. They can remove up to 20% of particles sized between 0.3 to 10 microns. However, they aren’t great at removing the dust, dander, and pollutants that cause asthma and allergies. So they may not be the ideal air filter for keeping your family safe.

For this reason, the lower MERV-rated air filters are only recommended for use in more spacious industrial settings where airflow is already good. Industrial settings also use a range of filters to help boost the air quality. They’re also useful in window air-conditioning units.

A MERV rating of 1-7 means the filter will remove:

  • Textile and carpet fibers
  • Sanding dust
  • Dust mites

MERV Rating 8-13

The best air filters for allergies are high-quality, HEPA-type filters with a rating between 8 and 13. These fit into most standard HVAC systems and provide superior protection from dust, pollen, mold spores, and other airborne allergens.

A good filter should trap at least 90% of particles in a size range 0.3 microns to 10 microns. A higher MERV rating means the air filter traps more of these particles. As a result, you improve your indoor air quality, keeping you and your family healthier.

A filter with a MERV rating of between 8-13 should be able to filter out particles like:

  • Dust mites
  • Mold spores
  • Pet dander
  • Pollen
  • Hair spray
  • Auto fumes

However, these higher-rated filters aren’t as cost-efficient and can result in slightly higher energy bills. So weigh up if the cleaner indoor air is worth the extra costs. The number of people living in your home, and the pollutants present in the area you live can help determine your MERV rating. Textile and

MERV Rating 14-20

Hospital-grade air filters are typically rated MERV 14-20 and are used in hospital settings to reduce the spread of infection. These filters can trap small particles like bacteria and viruses, making them ideal for use in environments where infection control is important.

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Higher grade filters are also used in settings where there may be carcinogenic materials, like manufacturing facilities. This is because they can filter out particles down to less than 0.3 microns.

Understanding the MERV rating of your filter is important because it can tell you how well your air filter will work. This, in turn, will help you keep your home air pollutant-free while also saving on your energy bills.

Need more help selecting the right air filter for your HVAC system? Contact the experts at SWAN today.

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