MERV 11 vs. MERV 12: What Is The Difference?

The MERV rating of air conditioners means the minimum efficiency reporting value. This is a rating system that you can use to determine the efficiency of air filters.

You need the right MERV rating for the filter of your HVAC system. A too low MERV rating will not help you. You may end up with contaminants in your living space. A too high MERV filter will restrict airflow. This may damage the internal components of your air conditioning unit.

But what is the difference between MERV 11 and MERV 12? What are the similarities between these two ratings? When should you use MERV 11? When should you go for MERV 12? If you have these and related questions, read on for accurate answers.

What is Merv 11?

MERV stands for minimum efficiency rating value. It helps you to determine the efficiency of an air filter. The MERV rating system ranges from 1 to 16. A MERV 16 air filter can trap the most minute particles. A MERV 1 air filter can trap only the large particles in the air.

A MERV 11 air filter efficiently removes more than 85% of larger particles. These are usually large dust particles, smoke, and pet dander. Such particles measure from 3 to 10 microns in diameter.

A MERV 11 air filter will trap between 65% and 79% of the average particles. These are the particles that measure between 1 and 3 microns wide. But a MERV 11 rating is not exceptionally effective in removing finer particles. As a result, it will struggle to remove microorganisms that may cause allergic reactions.

MERV 11 rating is unique because of its minimal effect on airflow. Higher MERV ratings restrict airflow. This piles pressure on the HVAC system. A MERV 8 filter is usually enough for domestic use.

It will remove all the common contaminants and keep your indoor air quality high. But you may need a MERV filter with a higher rating than 8.


  • Causes a lower level of pressure drop on the HVAC system
  • Such an air filter is powerful enough to remove average and large solid contaminants
  • It can remove bad odors from the house
  • It performs much better than MERV 8 filters


  • It is not efficient enough to remove all the fine air particles.
  • It may restrict more airflow compared to lower MERV ratings like MERV 8

What is Merv 12?

MERV 12 is one of the most effective HVAC filters for home use. It is a unique filter because it is more efficient than MERV 8 and even MERV 11 filters. A MERV 12 filter will remove up to 90% of large particles from the air. It is also equally effective in removing average particles such as pollen dust mites. 

A MERV 12 furnace filter may restrict airflow. When this happens, your HVAC systems may develop mechanical problems. You may realize this when you notice too much dust in the air vents.

Also, the AC unit may start getting very warm. This usually shows a problem with the airflow because of the filter. The higher the rating, the more likely it will restrict the airflow.


  • More effective than MERV 8 air filters
  • It can remove bad odors from indoors
  • It is much better than fiberglass air filters
  • It can prevent mild and even severe allergies


  • It is not as efficient as HEPA filters
  • It may damage the heating and cooling system because of restricting airflow and a high-pressure drop.

Merv 11 and Merv 12 Filters: In-Depth Comparison

Merv 11 vs. Merv 12: Allergen Removal Capabilities

Allergens are small particles that may cause allergies. People are allergic to different allergens. Some common allergens include dust and smoke particles.

When these particles are in the air, some people may start experiencing breathing problems. The allergies may be mild or severe.

Filters help prevent severe allergies by removing the small particles from the air. More expensive filters can remove all types of fine particles from the air. When choosing the best filter for your home, you should consider the MERV rating.

The higher the MERV rating, the greater the percentage of allergens that the filter can trap. A higher filter will be more effective in removing allergens than a lower one.

MERV 12 is more capable of removing allergens than MERV 11. A MERV 12 furnace filter will remove the following particles: pet hair, dust, pollen mite, and others.

This explains why MERV 12 is excellent for residential use. It can keep the indoor environment free of common allergens that usually cause allergies.

Merv 11 vs. Merv 12: Mold Reduction Capabilities

Mold can cause serious problems in your home. You need an air filter that can remove mold and spores from the air in your home.

Unfortunately, not all air filters can do this. For example, furnace filters with very low MERV ratings are ineffective in removing mold from the air. You need an air filter with a higher MERV rating.

Typically, air filters with MERV 8 and above ratings are good at removing mold. But there are important differences in their performance.

For example, a MERV 12 air filter is more effective in removing mold than a MERV 11 air filter. In addition, the MERV 12 air filter can trap and remove mold from the air than air filters with lower ratings.

But remember, air filters with very high MERV ratings usually interfere with airflow. If you go for very high MERV ratings, you may have a damaged HVAC system. So, you must balance the need to remove mold and maintain your air conditioning system.

Merv 11 vs. Merv 12: Odor Removal Capabilities

Foul odors come from many different sources. Some of the most common ones are cooking and sewers. Others include smoking, cleaning products, and liquor.

The presence of bad odors reduces the indoor air quality of your home. So, you need to get rid of them as soon as possible.

Both MERV 11 and MERV 12 furnace filters can remove bad odors from your home. Any air filter from MERV 8 can remove odors. However, a MERV 8 furnace filter causes less pressure drop than those with high ratings.

This is because the furnace filters have carbon particles on their surfaces. The carbon particles attract and trap the particles that cause bad smells in your home.

High MERV filters are more effective in removing bad odors than low MERV ones. So, your MERV 12 furnace filters will be better than the lower-rated ones in removing bad odors.

The only problem with using higher-rated filters relates to pressure drop. They tend to restrict airflow and create high levels of pressure drop. So, using a higher MERV rating comes with the risk of having a damaged HVAC system. 

Merv 11 vs Merv 12: Efficiency

MERV 11 is efficient in removing average particles. Some of the particles that MERV 11 furnace filters can remove are pet dander, dust mites, and cement dust. Others include carpet fibers, milled flour, and auto emissions.

However, MERV 11 rating struggles when it comes to removing finer particles. You cannot depend on MERV 11 to create a sterile environment. The good news is that you do not need a sterile environment in a typical home. Thus, you can use a MERV value of 11 to protect everyone from average particles that typically contaminate indoor air.

Although MERV 12 is not the highest MERV rating, it does well. MERV 12 is highly efficient in removing finer particles. You can depend on it to remove particles like lead dust and humidifier dust.

It is also effective enough to protect you from mild allergies. Airborne microorganisms usually cause such allergies. A MERV 12 air filter can successfully trap contaminants and keep everyone safe. It can also effectively trap large particles that measure more than 3 microns wide.

Merv 11 vs Merv 12: Particle Size

MERV 12 can trap higher percentages of smaller particles than MERV 11. You can notice this if you use pleated filters with MERV 12 ratings. Higher MERV ratings always mean great efficiency.

MERV 12 furnace filters can trap between 75% and 85% of mid-sized particles. Mid-sized particles usually measure between 1 and 3 microns wide.

MERV 12 can also trap about 90% of large dust particles. Such particles usually measure between 3 and 10 microns in diameter.

However, MERV 12 is not particularly effective in removing the smallest particles like microbes. Such particles usually measure between 0.1 to 0.3 microns wide.

MERV 11 rating is similarly not effective in removing the smallest particles. However, it is enough for removing large particles. Such particles usually measure between 3 and 10 microns wide.

MERV 11 can remove up to 85% of such airborne particles. Also, MERV 11 is enough for removing mid-sized particles. Examples of such particles are mold spores and auto emissions. MERV 11 furnace filters can remove between 65 and 79% of such particles.

Stand out Features of Merv 12 Air Filter 

Some people believe that the difference between MERV 11 and MERV 12 is negligible. But this is not the case. There are important differences between these two ratings. The differences are evident in how the two behave in your HVAC systems.

Also, the average particle size efficiency of the two ratings is different. If you are looking for a higher level of indoor air quality, go for MERV 12. MERV 12 rating furnace filters can remove many smaller particles than MERV 11 ones.

Although MERV 12 does not provide a sterile environment, it is excellent. It can help maintain clean air indoors by removing small particles, like pollen and dust mites.


Always check the MERV rating of air filters before purchasing one. It is not always advisable to use air filters with high MERV ratings. Sometimes, a low MERV rating may be better than a higher one.

For example, going for a MERV 8 air filter may be wise. But if you would like a higher MERV rating, you may have to choose between MERV 11 and MERV 12.

Use a MERV rating of 11 if you are keen on balancing efficiency and airflow. MERV 11 air filters will remove between 65% and 79% of average-sized particles.

Most of the solid contaminants in homes fall within this category. They include pet dander and dust. Also, the filter will not restrict the airflow in your HVAC system.

Use MERV 12 if you are keen on having high MERV filters in your system. Such filters are efficient in removing finer particles.

A MERV 12 furnace filter will remove odors and smaller particles that measure between 0.1 and 0.3 microns wide. But air filters with high MERV ratings usually restrict airflow. Any air filter higher than MERV 8 may restrict airflow and damage your system.

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