What Is The Difference Between MERV 10 And MERV 11?

This brief article is about MERV 10 and MERV 11 furnace filters. Air filters with this range of MERV rating are commonly used in homes and light industrial settings. They can remove small as well as large contaminants from the air.

However, it would help if you were sure about the specific rating that you choose. This is because there are slight differences between the two. This article discusses a few similarities and differences in performance between the furnace filters with these MERV ratings.

We also discuss the different categories of MERV ratings and the kind of contaminants that they can remove from the air in your home or any other premise.

Both MERV 10 and MERV 11 fall within the third group of MERV ratings which ranges from 9 to 12. Such MERV ratings are effective in removing contaminants that range in size from 1 to 3 microns wide.

They are typically used in residential as well as general commercial premises. Both MERV ratings are good for removing smoke from cars, fine dust, as well as spores, and other small contaminants. Therefore, it does not matter for general home use whether you choose MERV 10 or MERV 11.

However, a few subtle differences between furnace filters rated MERV 10 and those rated MERV 11. One of the main differences is in the level of airflow resistance. Generally, the higher the MERV rating, the higher the level of airflow resistance. Thus, a MERV 11 furnace filter will demonstrate a higher level of airflow resistance than a MERV 10 furnace filter.

MERV 10

MERV 10 is powerful enough to keep your home free of small and large contaminants. Therefore, it may be a good idea for a MERV 10 air filter with a pleated and electrostatically charged surface.

Such a furnace filter performs exceptionally because it attracts and traps large and small airborne contaminants. Compared to lower MERV ratings, MERV 10 may slightly interfere with airflow in your HVAC system.

However, the level of airflow resistance that a MERV 10 furnace filter may demonstrate is not as high as that which a MERV 11 or higher furnace filter may produce.

MERV 11

MERV 11 is ideal for use in homes as well as general business premises. Although MERV 11 furnace filters cannot trap disease-causing microorganisms, they do well in attracting and trapping small contaminants that measure between 0.3 and 1.0 microns. This means that such furnace filters can trap spores, fine dust from your humidifier, and small textile materials from your seats and carpet.

Compared to lower MERV ratings, MERV 11 may slightly interfere with airflow in our system. This means that it may be a good idea to go for a slightly lower MERV rating to balance between protecting your HVAC system from damages and maintaining a high Indoor Air Quality.

What is MERV Rating?

The Minimum Efficiency Reporting Values (MERV) measure the percentage of contaminants that a furnace filter can remove from the air. The size of contaminants varies greatly but falls within the following range: 0.3 microns to 10 microns. Therefore, this measure represents the diameter of the contaminants.

The MERV rating was developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers. This is a professional body that is usually known by the abbreviation of its name: ASHRAE.

ASHRAE developed a complex testing method that can be used to predict the percentages of the different types of contaminants that any air conditioner can successfully eliminate from the air.

The MERV rating scale ranges from 1 to 16. The higher the MERV rating, the higher the percentage of contaminants that it can remove. This means that higher MERV ratings are ideal for removing microparticles.

Low MERV ratings are perfect for trapping large particles. Thus, you can use MERV ratings to assess and compare the performance of two or more air filters. You can also use the MERV rating to determine the right kind of furnace filter for your home or any other premise.

What are the different Categories of MERV Ratings?

There are four different categories of MERV ratings. The categories are based on the size and percentage of the particles that the furnace filters can effectively trap. Therefore, you can use the MERV rating categories to determine the most appropriate air filter for your premises.

The first group comprises air filters with MERV ratings of between 1 and 4. Such furnace filters are designed to trap contaminants that are about 10 microns wide.

The furnace filters that fall within this group are typically used in residential window AC units. Furthermore, the furnace filters are perfect for trapping cockroach debris, sanding dust, and small-fiber particles from the carpet.

The second group comprises filters that have a MERV rating of between 5 and 8. MERV rating 5 to MERV 8 is ideal for removing contaminants that are 10 to 3 microns in diameter. This includes mold spores and dust mites.

The third group of MERV rating comprises furnace filters that measure 9 to 12 and are suitable for trapping contaminants 1 to 3 microns wide. Such furnace filters are ideal for trapping a wide range of contaminants, including dust from humidifiers, emissions from cars, and the tiny particles used to make products such as air fresheners and other aerosols.

The fourth group of MERV ratings ranges from 13 to 16. Furnace filters with high MERV ratings are perfect for trapping very minute contaminants from 1.0 to 0.3 microns in diameter.

Such microscopic particles include disease-causing microorganisms. This is the reason for furnace filters with this range of MERV ratings are used in hospitals.

Is a Higher or Lower MERV Rating Better?

It can be pretty tricky to decide whether you need a higher or lower MERV rating. Generally, a lower MERV rating serves you right if your house is full of large contaminants, including sawdust and others.

Low MERV rating do well when you need to rid the air in your home of such large contaminants. But the most significant advantage of using a low MERV rating is that they do not undermine airflow.

A higher MERV rating is necessary for the removal of fine-sized contaminants. For example, some furnace filters with very high MERV ratings can remove up to 90% of very tiny contaminants that measure even 0.3 microns. These are contaminants that you cannot see with your blind eye.

The worst part of choosing a very high MERV rating relates to airflow. High MERV ratings are associated with restrictions in airflow. This means that you will be forced to repair your HVAC system or even replace it when the blower gets damaged. Thus, the choice of which MERV rating is the right one for you depends on the actual circumstances in your home.

Conclusion

The MERV rating of a furnace filter is an important indicator of its performance. Ideally, the higher the furnace filter, the better the performance of the air filter. However, this is not always the case. It would help if you considered the extent to which the furnace filter may restrict airflow. High MERV ratings are associated with airflow restrictions.

On the other hand, very low MERV ratings are not enough to remove microparticles that may be contaminating your room. Therefore, you must balance between the performance and the safety of your HVAC system when choosing the proper MERV rating to use. MERV ratings of either 10 or 11 seem good enough to give you a balance between these two competing needs.