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What Is a MERV Rating? Your Complete Guide to Air Filtration

Since HVAC systems cost around $29 billion to American homeowners annually, you want to make sure that you get the most bang for your buck. However, you don’t want to overwork your air conditioner, either. Doing so wastes electricity and has poor environmental ramifications.

Choosing the right MERV rating for your HVAC system is the best way to save both money and energy. But what is a MERV rating?

Here, we’re going to answer this question. We’ll also help you figure out the rating that will give you the highest air quality at the lowest cost. Read on for your complete guide to MERV ratings so that you can select the right filter.

What Is a MERV Rating?

The Minimum Efficiency Reporting Value (MERV) of an HVAC system is a measurement of the particle size that a filter can catch. The system was designed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers.

The MERV scale ranges from 1-20. The number given as the rating indicates the size of the particles that the filter is able to capture. Lower numbers can only capture extremely large particles while higher ones can capture just about anything.

Note that when shopping for HVAC filters, you need to pay specific attention to the MERV rating as indicated on the packaging. Do not get confused by packaging that uses a different rating system. You don’t want to accidentally get the wrong type of air filter.

Your Comprehensive MERV Rating Guide

So, what type of particles can air filters catch? That depends on the precise MERV rating of the filter. You need to understand the different MERV rating ranges so that you know what filter you need to get.

Note that higher-rated filters can pick up all of the same particles as those with lower ratings. They simply can also filter out additional particles.

MERV 1-4

These filters can only capture particles of >10.0 μm. You can, in fact, see most of these particles with the naked eye. They include dust mites, pollen, spray paint/sanding dust, carpet fibers, and debris from household pests.

Because of their low rating, they’re fairly ineffective. They only are really ever used for residential window units. They generally aren’t even the right choice for these applications, either, so you likely want to avoid MERV 1-4 filters altogether.

MERV 5-8

Most residential air filters have ratings ranging between 5-8. They filter particles anywhere between 10.0–3.0 μm.

These filters pick up mold and other spores and therefore are necessary for effective filtration. They also improve air quality by eliminating dusting aids, hair spray, and pet dander. As a result, they’re usually used for residential and commercial spaces as well as some industrial ones.

MERV 9-12

These filters pick up particles between 3.0–1.0 μm. They’re better than other, lower-rated residential and commercial air filters. They also are high enough a level to be used in lab and hospital spaces.

MERV 9-12 filters can filter out auto emission particles, lead dust, milled flour, and similarly-sized particles. These filters are optimal for most applications.

MERV 13-16

Merv 13-16 filters can eliminate particle sizes between 1.0–0.3 μm. This means all bacteria and nuclei from sneezes. Cooking oil, smoke, and paint pigments are among the things that these filters can eradicate.

Because of their ability to eliminate all bacteria and make a space sterile, these filters are usually used in hospitals. They make for good filtration systems in general surgery wards.

MERV 17-20

These filters provide the highest ventilation on the market. They catch particles < 0.3 μm. This includes viruses, carbon dust, and all smoke (rather than simply thick smoke).

They generally are used in manufacturing cleanroom facilities in the electronics and pharmaceutical industries.

How to Choose a MERV Rating

As a homeowner or someone who owns a commercial space, you likely are wondering whether or not you should get the highest possible MERV rating. After all, wouldn’t a MERV 20 filter always work better than a MERV 8 one?

The answer to this is a resounding ‘no.’ You do not want to get a filter with a rating above 12 unless you have very specialized applications. If you don’t know what these applications are, you almost certainly are not involved with them.

You likely will need a filter anywhere between MERV 5-12. Generally, 7, 8, or 9 is the best option.

But why is this the case?

Of course, a filter with a rating beneath 5 is going to be completely ineffective. You need something that can catch all of the dust and bacteria around your home. Even filters rated 5 and 6 probably won’t catch the particles that you want to eliminate.

On the flip side, filters with too high a MERV rating will also provide you with poor air quality. There will be virtually no chance for good air particles to circulate, which makes it more difficult to breathe.

Additionally, HVACs with too-high MERV ratings will work too hard to continue operating. You’ll increase the risk of your system breaking down and needing replacement. Additionally, this will waste a lot of money on electric bills.

Upgrade Your Air Filtration System Today

So, what is a MERV rating?

It’s basically the concept that tells you how effective your HVAC system will be. That’s why it’s important to pay attention to your specific needs and the rating that will best work for your space.

Contact us with any remaining questions that you have on choosing an air filtration system. We’ll help you assess the level of filtration that you need so that you can best eliminate harmful particles from your air. Since we’re committed to helping you preserve your air quality, we look forward to getting in touch.

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