MERV Rating Chart
A MERV rating chart gives you a way to compare how well different air filters capture and hold airborne particles. MERV stands for Minimum Efficiency Reporting Value, and it’s an industry-standard system used across the board. The ratings range from 1, which represents the lowest efficiency, up to 20 for the highest-performing filters.
This system was designed so that consumers and professionals alike could compare filters from different manufacturers on a level playing field. It tells you how effective a filter is at trapping dust and other particles of various sizes. The chart you’ll see below breaks that down — showing which particle sizes are captured at each MERV level, and what percentage of particles a filter is expected to remove at that rating.
It’s worth noting that in January 2009, ASHRAE (the American Society of Heating, Refrigerating and Air-Conditioning Engineers) officially stopped recognizing MERV ratings above 16. However, MERV 17 through 20 are still widely referenced in the filtration industry, especially when talking about HEPA and ULPA filters. So, while they aren’t part of the current ASHRAE standard, we’ve included them here because they’re still commonly used in real-world conversations and comparisons.
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This Video Explains the MERV Filter Rating Chart
Higher Values = More Filtration in the MERV Filter Rating Chart
Generally, the higher the MERV rating, the better the filter performs. That’s not always the full story, but it’s a good starting point. MERV values range from 1 up to 20, and each level tells you something about what kind of particles the filter is designed to catch, and how efficiently it does it.
MERV 1 through 4 filters are on the low end of the scale. These are built to capture only the largest airborne particles. They’re not really there to protect people — they’re more about protecting the equipment. You’ll see these in residential furnace systems or in some light industrial settings where dust control isn’t a huge concern. Their average efficiency in removing particles from 3 to 10 microns is under 20 percent. This range is rated using something called average arrestance — that’s just a measure of how well it holds on to large debris. If you’re trying to picture how effective that is, think of a lint trap in a clothes dryer — that’s about a MERV 2.
As you go up the scale to MERV 5 through 8, you’re getting into finer filtration. These filters are capable of removing smaller particles — things like household dust, pollen, and some mold spores. At this level, the focus shifts a little more toward protecting people and products from airborne irritants that can affect health or productivity. You’ll find these filters in more conscientious residential systems, some office buildings, and commercial spaces that want to maintain a higher standard of cleanliness.
MERV 9 through 12 is where things start to get serious for indoor air quality. These filters can trap particles that are small enough to cause respiratory issues — things like fine dust, pet dander, and certain allergens. They strike a good balance: they remove a large percentage of harmful particulates, but they still allow enough airflow to keep most HVAC systems running smoothly. That’s important because if a filter restricts airflow too much, the system’s blower motor can overheat. MERV 9 to 12 filters are what I’d call a practical sweet spot for most homes and offices — they’re effective, reasonably priced, and won’t put too much strain on your system.
Once you move into the MERV 13 through 16 range, you’re dealing with high-performance filters. These are capable of capturing much smaller particles — down to 0.3 microns — and are often used in hospitals, clean rooms, or dedicated air purification systems like our LakeAir units. They’re not recommended for standard home HVAC systems because they do restrict airflow significantly unless you’ve got a blower that’s specifically designed to handle the added resistance. This level of filtration is best reserved for serious applications where air quality is critical, or where a dedicated purifier can do the heavy lifting.
At the top of the scale — MERV 17 through 20 — you’ll find HEPA and ULPA filters. Now technically, ASHRAE stopped recognizing these higher MERV numbers in 2009, but they’re still commonly referenced in the industry for comparison purposes. These filters are in a class of their own. They remove at least 99.97% of particles and can even capture things like viruses and radioactive material. They’re not designed for HVAC systems — they’re used in stand-alone purifiers, medical environments, and other places where ultra-clean air is absolutely necessary. In our own product line, many of our most effective smoke eaters — the ones built to handle cigar and tobacco smoke — rely on True HEPA filters in this range.
LakeAir Filters: Built for the Real World
At LakeAir, we don’t believe in one-size-fits-all filtration. Our systems use a variety of filters, each tailored to a specific job — from light residential use to serious commercial air cleaning. Every unit is designed around performance, reliability, and real-world needs.
Recomendations from an Expert in Air Filtration
We start simple. Our pre-filters are rated MERV 2 — basic, but essential. They catch the big stuff before it reaches the finer stages. From there, we use MERV 10 filters in our furnace-style frames. These strike a nice balance between airflow and efficiency. For everyday use, that’s a good filter. Reliable. Affordable. Easy on fans and blowers.
Need something with a bit more muscle? Our media air purifiers use MERV 11 filters. This level is perfect for households with pets, or folks who are sensitive to allergens like mold, smoke, and pollen. It’s what we call our “better” filter — better airflow than high-end HEPA, but strong enough to trap the stuff you don’t want in your lungs.
Now, when you move into our commercial units, things get more serious. These machines can be equipped with our HC-14 — a High Capacity MERV 14 filter. It’s a 4-inch thick beast with over 60 square feet of dirt-grabbing surface. It catches particles down to 0.3 microns with 75% efficiency, and ramps up to 95% on the larger stuff. The galvanized steel frame keeps it sturdy, and the 0.22 inches of water gauge back pressure means it won’t choke your system. It’s tough, efficient, and built to last.
We also offer MERV 15 filters for environments where near-HEPA performance is needed, but ultra-fine capture isn’t critical. These filters are a smart choice in shops and commercial spaces where cost, airflow, and filtration need to stay in balance. You’ll get high performance without the full cost or airflow restriction of a HEPA.
Speaking of HEPA — yes, we’ve got those too. Our HEPA filters are the top tier, removing 99.97% of all particles, including microscopic contaminants. These are for customers who need the cleanest possible air. They’re not made to fit inside your furnace, but they’re perfect in standalone purifiers for homes and businesses.
Then there’s electrostatic filtration — a different animal altogether. Comparing electrostatic to media filters is like comparing apples to oranges. They’re measured differently, they perform differently, and they behave differently in the field. Still, our electrostatic filters stack up to about a MERV 16 in performance. And here’s the kicker — they’re washable. They never need replacing. That makes them a favorite in homes that want serious filtration without ongoing costs. The Maxum electrostatic unit is a great example — plug it in and forget about it.
And no matter which filtration method you choose, there’s one piece of advice we always give: make sure your system includes activated carbon. ASHRAE tests don’t measure for odors or volatile organic compounds (VOCs), but those are real pollutants — especially in homes with smoke, cooking odors, or chemical fumes. Activated carbon handles what traditional filters can’t.
If you’ve got questions, we’re here. Call our team at 800-558-9436. We’ll walk you through your options and help you find the filter or system that fits your space, your budget, and your air.
Merv Rating Test Procedure
How the MERV Rating Test Works
The MERV rating system wasn’t just pulled out of thin air — it was developed by ASHRAE. The official testing method behind the numbers is called ASHRAE Standard 52.2-2007, and it’s all about measuring how well a filter removes dust and particles from the air.
At its core, the test looks at how effectively a filter captures particles in the 0.3 to 10 micron range — which covers everything from fine smoke particles to larger bits of dust and debris. The goal of the standard is consistency. That way, no matter which manufacturer made the filter, you’re getting a reliable comparison based on actual lab results.
Here’s how it works: the test always starts with a clean filter. Over the course of six test cycles, a controlled amount of dust is introduced into the airflow. That dust is sorted into three particle size groups — from the very fine stuff you can’t see, to larger airborne debris. During each cycle, the filter’s ability to trap those particles is measured.
What makes the system unique is that the filter’s lowest performance level across all six tests is the one that gets reported. That’s why it’s called the Minimum Efficiency Reporting Value — the MERV rating doesn’t just show what a filter can do at its best, but how well it performs under baseline conditions. In most cases, that’s when the filter is brand new and hasn’t had a chance to load up with dust yet.
The test begins with a clean filter. The test is made of six cycles. During each cycle a predetermined amount of dust particles is released into the airstream. These dust particles fall into three size groups.
Testing Different Particles Sizes and Understanding Particle Groups E1, E2 and E3
Once the test begins, the filter is challenged with three groups of particle sizes — E1, E2, and E3. These represent fine, medium, and large particles, ranging from 0.3 to 10 microns. The amount of each group that the filter captures — and the amount it lets through — is measured.
This isn’t just a one-time test. The process is repeated six times, and here’s the important part: the lowest recorded performance across all three particle groups during those six test cycles is what determines the filter’s final MERV rating. That’s where the “Minimum” in Minimum Efficiency Reporting Value comes from — it’s not the best-case result, it’s the baseline.
The amount of E1, E2 and E3 dust particles that are captured and missed is calculated. The process is repeated 6 times. The poorest performance of the filter on all three particles sizes during each of the 6 cycles is used to determine the filters MERV rating. The poorest performance is used. This is how they get the name MERV (MINIMUM Efficiency Rating Value).
Arrestance
Arrestance is a term often used in describing filter performance. Arrestance is a measure of the ability of an air filtration device to dust from the air.
Each particle group is tied to real-world examples. E3 particles (3 to 10 microns) include common visible debris like dirt and lint. E2 particles (1 to 3 microns) represent things like milled flour or welding fumes. And E1 particles, the smallest of the three at 0.3 to 1 micron, include things like bacteria and tobacco smoke — the stuff you can’t see but definitely don’t want to breathe.
The Chart to the right shows the scale used to evaluate each of the 6 test cycles. While it is not important to fully understand the comparison chart, it is good to familiarize yourself with it. The informed consumer is a powerful force in the marketplace.
Filter Application Chart
What These Test Speeds Mean
MERV ratings are based on how well filters capture different particle sizes — but airflow velocity plays a big role too.
Filters are tested at several different airspeeds, ranging from slow residential duct flow (118 FPM) to intense industrial conditions (748 FPM). These speeds simulate how filters might perform in real-world HVAC systems.
But only one speed is used to determine the final MERV number:
492 FPM (2.5 m/s) — the ASHRAE 52.2 standard.
That’s the speed shown in test results, and the one to compare against your own system.
Why This Matters for Your System
Let’s say you install a MERV 13 filter rated at 492 FPM… but your airflow is only 295 FPM.
Your filter may perform even better than its rating.
If your system runs faster — say 630 FPM — you might lose a bit of efficiency.
That’s why we show the whole range. Whether you’re working with:
Residential HVAC ducting (295–374 FPM)
Commercial systems (492–630 FPM)
Special use cases like cigar lounges
…it helps to know where you fall on the scale.
💡 Need help estimating your system’s airflow?
Use our Room Calculator or give us a call — we’re happy to help.
Wrapping it up for you the Website Visitor
Understanding how MERV ratings are calculated gives you a deeper sense of what you’re really buying. It’s not about hype or claims — it’s about how a filter performs under stress, across multiple real-world conditions.
Whether you’re managing air quality in your home, your business, or a smoke-heavy environment like a cigar lounge, MERV ratings offer a reliable guide. They’re rooted in lab-tested science, but they apply directly to the air you breathe every day.
And if any part of this still feels overwhelming — don’t worry. You don’t have to be a filtration engineer to make a smart choice. That’s what we’re here for.
Need More Help?
Still unsure which MERV level suits your space? Give us a call at 800-558-9436, and we’ll walk you through it. Simple as that.
Frequently Asked Questions
A MERV rating is a numerical rating system developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters. The MERV rating system goes from 1 to 16, with the higher numbers representing filters that can remove smaller particles from the air.
The MERV rating is a measure of the ability of an air filter to remove particles from the air. The higher the MERV rating, the more efficient the air filter is at removing particles. The MERV rating is determined by the size of the particles that the air filter can remove, with the smallest particles being the most efficient at removing. The MERV rating is a scale from 1 to 16, with the higher numbers being the most efficient at removing particles.
There are many benefits to having a higher MERV rating, including:
- Increased efficiency of the HVAC system – a higher MERV rating means that the filter is able to capture more particles, which leads to a more efficient HVAC system.
- Improved indoor air quality – by capturing more particles, a higher MERV rating results in cleaner air being circulated throughout the home or office.
If you have a high MERV rating, you should change your filter every 3 months.
This depends on a variety of factors, including the type of air filters you have, the size of your home, the number of people in your household, the presence of pets, and your own personal preferences. However, if you are noticing that your air filter or smoke eater are not working as efficiently as it used to, or if you are constantly having to clean your air filters, it may be time to upgrade to a higher MERV rating.