How to choose the proper MERV rating ?

How to choose the right MERV rating?

Few people know that there are many options for air filters, and the MERV rating is one of the most important factors you need to consider because it represents filtration efficiency. All of us desire to have high air quality in our homes.

When choosing a suitable MERV, you can be guided by the effect of the MERV rating:

MERV-1 to MERV -4: Filters out pollen and carpet fibers.

MERV-5 to MERV -8: Removes mold spores, pet dander, and highly allergic dust mite feces.

MERV-9 to MERV -12: Removes lead dust and most bacteria.

MERV-13 to MERV -16: Captures viruses, bacteria, and coal dust.

However, higher MERV values do not mean higher filter efficiency, and filter efficiency is related to many other factors. Learn more about how to select a MERV in this article.


What is MERV?


MERV rating represents the minimum efficiency rating value, which is a measurement system that is nationally recognized and was used to access each air filter. The MERV rating depends on the capacity of capturing the particles. The range of MERV rating is also from 1 to 20, 20 is the highest, and 1 is the lowest.

Know more about: All about MERV ratings


What is the best MERV rating to use?


Depending on your needs for air filtration, there is likely a MERV rating that will meet your requirements. The table below displays the different MERV ratings and their typical uses as well as the material and shape they are most commonly made of.


MERV Rating



Typical Air Filter Material

MERV-1 to MERV-4

Normal filter

Cuts down on carpet fuzz and lint, but doesn't block much else.

ü Pre-Filter In Commercial Building

ü Residential Furnaces

ü Window Air-Conditioning Unit


ü Fiberglass

ü Washable aluminum

ü Synthetic mesh


MERV-5 to MERV-8

Representative filter

Keeps away common dust, pollen, and some mold spores.

ü Pre-filters or Final Filters

ü Commercial Buildings

ü Industrial Workplaces

ü Paint Booth Inlets


ü Pleated cotton

ü Polyester


MERV-9 to MERV-12

Good filter

Filters out most common air pollutants, such as mold spores, smog, fine dust, and pet dander.

ü Hospital Laboratories

ü Better Commercial Buildings

ü Superior Residential Buildings


ü Pleated cotton 

ü Microfine fiberglass

ü Usually 2" thick or more


MERV-13 to MERV-16

Better filter

Stops tiny airborne things like bacteria, viruses, and smoke.

ü General Surgery

ü Superior Commercial Buildings

ü Hospital Inpatient Care

ü Smoking Lounges

ü Pleated cotton

ü Microfine fiberglass

ü Usually 4" thick or more

How does the MERV rating system work?

The MERV system is the industry-standard air filter rating system. It was established by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE).

ASHRAE standard 52.2 describes the methods and procedures for evaluating the performance of air filters as a function of particle size. In layman’s terms, it sets forth the minimum amount of particles that a filter must capture in order to obtain a specified MERV rating.

As an example, if an air filter is capable of capturing at least 20% of E1, 65% of E2, and 85% of E3 particles, then it will receive a MERV 11 rating.


Air filter MERV Rating Table


The table below shows the minimum threshold that a filter must perform at in order to obtain a specified MERV rating. As the MERV rating goes up, the filtration efficiency requirements get more stringent.

Minimum % of particles removed by the air filter.

MERV Rating

E1 particles

(0.3 - 1.0 microns)

E2 particles

(1.0 - 3.0 microns)

E3 particles

(3.0 - 10.0 microns)

MERV-1 to Merv-4





















































The highest MERV rating must not only be able to filter smaller particles but many more as well.

MERV 1 filters have not been tested for their ability to catch the particles which are both E1 and E2. This does not mean that these filters will not catch any E1 or E2 particles- they have just not been tested.

What are E1, E2, and E3 particles?

What are E1, E2, and E3 particles?

Particles range in size E1, E2, and E3 and they are used to determine the MERV rating of air filters.


E1 particles are sized between 0.3 to 1.0 microns. Standard particles found in this size range are smoke particles and bacteria. Only filters rated MERV 11 or higher are tested for such particulates.


E2 particles are sized between 1.0 to 3.0 microns. Common examples of E2 particles include dander from pets and the bacteria E. coli. These particles are up to 2.5 microns in diameter and include E2 particles. Filters need to be rated MERV 8 or higher to work with these types of particles.


A microparticle known as an E3 particle is measured in 3.0 to 10.0 microns in size. It is composed of household dust, pollen, or mold spores. The majority of air filters can capture E3 particles to some degree, but high-rated MERV filters can do this better than low-rated ones.


What kind of MERV rating is suitable for residential use?


There are some key factors that influence which type of MERV you should choose.

● The location of your house

● Your budget of the air filter

● The frequency of use of your air filter

● Do you have family members who smoke?

● Do you have pets in your house?

● If you have had members who have respiratory problems?

In general, air filters with a MERV rating of 6-13 are suitable for most homes. This range offers a perfect balance between airflow, air filtration, and affordability. If you choose the air filters with MERV 13, you can use them for at least six months.

What is the most appropriate MER rating for home use? It means your home will be cleaned without putting a strain on your HVAC unit and reducing airflow.

Is it time to change your air filter?


We generally recommend from 30 days for cheaper fiberglass glasses filters to 6 months for high-ended pleated filters, but the cheaper ones can’t work effectively. These are the assumed average usage and take the type and size into the consideration.

As for the pleated air filters, you are recommended to replace them every 90 days, if your ai filter captures much more allergens, dust, and pollen from the air, it harms the normal efficiency of the filter.

How to change the central AC or furnace filter in your home

Disconnect the device from power. Consult your appliance manual if you are not sure how to turn off the furnace. We don't want to run the furnace without a filter.

To remedy the door, either lock or unlock it and clean up as we discussed earlier.

Just double-check the filter type. If it's single-use, just change it with a new filter of the appropriate size.

If the filter is reusable, first use a brush to get rid of any surface grime and vacuum with a soft brush attachment to suck out more embedded dust and grime.

Flush the water from the opposite direction to the airflow in the shower to wash the dust and soot out.

Be sure to allow reusable filters to air dry thoroughly before reusing.

Do not turn on the HVAC until you've replaced the filter with a clean, dry one.

Which way does the air filter go in?

Place the arrow on the filter away from the return air ducts and point it in the direction of the HVAC equipment. The HVAC system moves warm or cold air around your home by using the natural movement of hot or cold air to the vents. This means that when you suck in a deep breath, the exhausted air should first pass through the filter before being circulated back into the home. Not clear? Another solution would be to keep the arrow facing the ceiling or wall. If your filter is mounted on a wall, the arrow should face the wall. When your filter is positioned at the ceiling, the arrow should point upwards.

If your air filter doesn't have an arrow on it, make sure you're not holding it upside down! (But seriously, they all have arrows on them.) On this occasion, it's important to pay attention to each side of the filter. The side of the filter with the wireframe should be facing out, and the side without the wireframe should be facing inward.

Some useful information for you: Once you know which way the air is going, mark it on the HVAC unit or ductwork with permanent markers. Next time you replace the filter, make sure you pay attention to the direction the arrow is pointing in so you don't get it backward, then you've replaced the air filter correctly.

start buying filters

Once you have decided which type of filter is best for you, there is one last and important consideration to make. Filters are the central working component of any filtration system, and it is crucial to choose only the most efficient and highest quality filters out there. 


TrightFilters is a high-quality, award-winning, and customer-vetted filter seller that assures you get the MERV-rated filters at an affordable price.  Get in touch  with us now to see what we have in store for you!


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