What Is The Difference Between MERV 11 And MERV 13?

One of the most common problems of high MERV ratings is that they restrict airflow. However, high MERV ratings are ideal for removing small and large contaminants.

Therefore, one must carefully think about these two competing issues when choosing the MERV rating of a furnace filter. In this short guide, we discuss two MERV ratings: MERV 11 and MERV 13.

We discuss important features of the furnace filters with these MERV ratings. Some of the things that we cover include their air filtration performance and whether they restrict airflow. The information will help you make an informed decision when choosing one.


MERV 11 is suitable for trapping contaminants that measure between 1.0 and 3.0 microns in diameter. Such contaminants include smoke from vehicles, dust from a humidifier, and droplets from aerosols.

MERV 11 is perfect for high-end residential and commercial buildings. This is because its ability to remove over 80% of small-sized contaminants is suitable for such places.

Thus, when you install an 11 MERV furnace filter in your home, you will enjoy an exceptionally high level of Indoor Air Quality. Besides, MERV 11 does not cause severe airflow restrictions, as is the case with higher MERV ratings like 13.


MERV 13 belongs to the fourth category of MERV rating. This category ranges from MERV 13 to MERV 16. Thus, a MERV 13 furnace filter will perform almost as well as a MERV 14 one. Therefore, you will hardly realize a difference in the air filtration performance of MERV 13 and MERV 14 air filters.

MERV 13 furnace filters can attract and trap very tiny solid contaminants. They can trap contaminants that are as small as 0.3 microns wide. For example, such furnace filters can trap microparticles from cooking oil, very fine droplets from people who cough or sneeze, and dust from the insecticide. These are usually very fine particles that can cause significant problems if they are left to accumulate in the air on your premises.

You will find MERV 13 air filters in hospitals and other premises where the air should be maintained clear of any form of contaminants. Such furnace filters are used in hospitals because MERV 13 is high enough to trap disease-causing microorganisms, including bacteria and viruses.

However, you may not have to use MERV 13 in your standard residential or even commercial premises. This is because the furnace filter may cause severe airflow restrictions and probably damage your HVAC system. A lower MERV rating is just enough to maintain a high Indoor Air Quality level in your standard residential or commercial premises.

What is the Best MERV Rating?

The American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) recommends MERV 11 to MERV 13 as the best for your home. Any air filter that falls within this range is powerful enough to attract and remove a broad range of solid air contaminants.

However, there are certain things that you must consider before settling on the right MERV rating for your home. Notably, you need to consider if your HVAC system can handle the MERV rating you are interested in. Your local technician may help you choose the proper MERV rating according to the technical requirements of your HVAC system.

It would help if you also considered the level of airflow restriction associated with your MERV rating of choice. For example, high MERV ratings are associated with greater levels of airflow restrictions.

Airflow restrictions will force your HVAC system to overwork. This will lead to higher bills of power. Furthermore, it may cause the components of your HVAC system to get damaged, thus leading to high repair or replacement costs.

Is MERV Rating 13 Ideal for Fighting Allergies?

MERV 13 is ideal for fighting allergies because it can trap up to 90% of various types of allergens. Allergens are tiny particles that cause allergic reactions in people.

Some people are susceptible to various allergens, including smoke, fine dust from a humidifier, microparticles from paint, and even small parts of fabric from the carpet and seats. Others are sensitive to small fur particles that come from pets.

The size of various types of allergens varies widely. Some allergens are very tiny, with diameters ranging from 0.3 to 1.0 microns, while others are slightly large. The significant allergens have diameters that range from 1.0 to 3.0 microns.

MERV 13 can attract and remove large as well as small contaminants. For example, a MERV 13 air filter can trap contaminants ranging from 0.3 to 1.0 microns. This means that if you install such a furnace filter, the indoor air in your premises will be free of all small contaminants that usually cause allergic reactions in people who are sensitive to them.

How Good is the MERV rating of 11?

MERV rating is good enough if you are keen on having a furnace filter with a relatively high MERV rating but conscious of airflow restrictions. High MERV ratings are perfect for removing large percentages of over 80% of small contaminants. MERV 11 is good enough to trap contaminants that are between 1 and 3 microns wide.

These are spores and other fine solid particles that cannot see with the naked eye. This means that MERV 11 is a good choice for maintaining the Indoor Air Quality of your premises high enough. You can comfortably use a MERV 11 furnace filter in your residential or commercial premises.

Although MERV 11 may restrict airflow, this is not as serious as other higher MERV ratings like 13. Thus, you can trust a MERV 11 furnace filter to do a great job of clearing the air in your home of all solid contaminants without interfering with the flow of air in your home.

However, compared to lower MERV ratings, MERV 11 may not be the best if you are keen on avoiding airflow restrictions.

Does MERV 13 Restrict Airflow?

MERV 13 can restrict airflow in your HVAC system. This is because MERV 13 furnace filters have high levels of pressure drops. Pressure drops are used to measure the extent to which a furnace filter can restrict the flow of air in your HVAC system.

The higher the pressure drop, the bigger the capacity of the furnace filter to restrict the flow of air in your system. Therefore, high MERV ratings have higher pressure drops than low MERV ratings.

Airflow restrictions are an unpleasant occurrence. It usually forces your HVAC system to overwork so that it can maintain the desired temperature in your home. When the HVAC system overworks, it consumes a higher amount of power than when it is working ideally.

This means that you will end up paying more for power when you use a high MERV rating furnace filter that restricts the flow of air in your HVAC system. Furthermore, airflow restrictions may damage your HVAC system. Replacing components or the entire HVAC system is usually a very costly thing to do.


MERV 11 is suitable for superior residential and standard commercial premises. MERV 11 furnace filters can collect contaminants that range in size from 1 to 3 microns in diameter.

MERV 13 is in the highest category of MERV ratings. A MERV 13 furnace filter can collect microparticles that measure between 0.3 to 1.0 microns. Such furnace filters are ideal for hospitals and other places where the air should be free of microorganisms and other microparticles.

You may not need to use a MERV 13 furnace filter in your standard residential or commercial property. Furthermore, MERV 13 may easily cause airflow restrictions. However, its performance is by far superior to that of MERV 11.