What Is The Difference Between MERV 6 And MERV 8?

Many people are hardly conscious of how the MERV rating of the furnace filter affects the airflow in their homes. However, there is a direct relationship between the MERV rating of your furnace filter and the airflow.

The rule of thumb is that the higher the MERV rating of your air filter, the greater the level of restriction of airflow. This brief guide examines the similarities and differences between MERV 6 and MERV 8 furnace filters.

MERV Rating 6

MERV 6 furnace filters are effective in removing common small and large contaminants. Some of the contaminants that such furnace filters can successfully remove include cement dust, mold spores, and hair spray.

You can rely on a MERV 6 furnace filter to successfully protect your loved ones from asthma and other breathing problems caused by solid contaminants in the house.

You can also use furnace filters with this MERV rating to remove odors from your room. Pungent smells come from contaminants in the bathroom, kitchen, and several other places in your home.

Having an air filter with the proper MERV rating of about six or higher may be enough to remove such bad smells and keep your home fresh and comfortable.

The furnace filters that have a MERV rating of 6 will trap large percentages of macroparticles. Such particles typically measure 1 to 3.0 microns in diameter. MERV 6 is usually enough to trap about 80% of such large contaminants, including dust and smoke.

Such furnace filters can also trap microparticles that measure between 0.3 and 1.0 microns. Such microparticles are commonly found in homes and industrial spaces. They can trigger asthmatic reactions in people who are sensitive to them. However, MERV 6 can capture only a relatively lower percentage of microparticles of about 40%.

MERV Rating 8

MERV 8 furnace filters perform better than MERV 6 ones. This is in terms of the percentages of large and small particles that they can attract. MERV 8 furnace filters can capture about 90% of large contaminants. Such contaminants measure 1.0 to 3.0 microns in diameter.

Also, MERV 8 furnace filters can capture microparticles that measure between 0.3 and 1.0 microns. Such microparticles include dander and small hairpieces from your pets. Unfortunately, such microparticles may also trigger allergic reactions, cause odors, or lower the Indoor Air Quality of your home.

MERV 8 is good for maintaining the Indoor Air Quality of your home. The Indoor Air Quality is measured by the percentage of contaminants found in the air in your premises.

The higher the percentage of available contaminants, the lower the Indoor Air Quality. To maintain Indoor Air Quality at high levels, you need to install a furnace filter with relatively high MERV ratings.

Such a filter, like the one with a MERV rating of 8, is powerful enough to remove airborne contaminants and keep the house safe, clean, and comfortable.

MERV 8 air filters that are pleated and have electrostatically charged particles are more effective than those with non-pleated surfaces. Therefore, you can for MERV 8 air filters that have pleated surfaces for a more comfortable, cleaner, and healthier indoor air environment.

How Does MERV Rating Affect My HVAC?

The relationship between MERV rating and HAVC is simple: higher MERV ratings are bad for your HVAC system. However, the details on how this happens are a little complicated.

For example, furnace filters have a unique feature referred to as pressure drop. Pressure drop is an important indicator of how the furnace filter can restrict the flow of air.

The higher the pressure drop, the higher the restriction. This means that furnace filters that have high MERV ratings also have correspondingly high levels of pressure drops.

As a result, such furnace filters trap high percentages of large and small contaminants. However, they are notorious for restricting the flow of air in your HVAC system.

When the furnace filter with a high MERV rating and a corresponding high-pressure drop level is installed in your house, it forces your blower to overwork. When the blower overworks, your HVAC system ends, making many more cycles to maintain the temperature in your home at ideal levels.

Unfortunately, this means that the blower or any other component of your HVAC system may get damaged. Repairing your HVAC system or even replacing a component is usually quite costly.

Therefore, you should always balance between the desire to achieve a high Indoor Air Quality and the need to protect the blower of your HVAC system when choosing a furnace filter for air filtration.

What is MERV Rating Best for Home Use?

Although it is difficult to determine the perfect MERV rating for your home accurately, anything from 8 to about 12 can be the best for home use. MERV ratings that range from 8 to 12 are the best for home use because of various reasons.

Primarily, furnace filters that have MERV ratings that fall within this range are ideal for trapping both large and microparticles. Microparticles can be particularly stubborn in your home because of their effect on sensitive people. Besides, getting the right MERV rating for trapping them may be challenging because particles are incredibly minute.

On the other hand, large particles usually measure from 1 to 3 microns in diameter. Such particles may also cause severe problems because of how they interfere with the Indoor Air Quality of your home.

Factors to Consider When Choosing the Best MERV Rating

Choosing the proper MERV rating may be one of the most important decisions you may have to make when purchasing a furnace filter. Apart from indicating the level of performance of the furnace filter, the MERV rating helps you determine the extent to which the furnace filter will restrict airflow.

Therefore, you need to put in some thought before you settle on the proper MERV rating. Here are a few important things that you should consider when choosing the best MERV rating for your furnace filter.


The general rule is that the higher the MERV rating, the more excellent the performance of your furnace filter. Furnace filters with high MERV ratings perform better than those with low MERV ratings.

High MERV ratings mean that the furnace filters can attract and trap large amounts of large and microparticles. Microparticles that usually contaminant the indoor environment measure from 0.3 to 1.0 microns wide. Such microparticles may be in the form of smoke, dander, and even hair particles from your pets’ fur.

They may trigger allergic reactions and other breathing complications in people who are sensitive to them. Thus, high MERV ratings are needed to remove such microparticles from the air in your room.


The higher the airflow, the higher the pressure drop. High levels of pressure drops mean that your furnace filter will restrict the airflow more than when the pressure drops are lower.

Airflow restriction may be pretty expensive in the long term. It may force your blower and HVAC system to overwork to ensure that the temperature in the home is maintained within the desired range.

In addition, if a component of the HVAC system gets damaged, you will be forced to incur additional expenses to repair or replace it.


Both MERV 6 and MERV 8 furnace filters are ideal for airflow because they are relatively low. There are many other brands of furnace filters that have very high MERV ratings of even 14.

Unfortunately, such furnace filters interfere with the airflow in your HVAC system. Although installing them may help keep your Indoor Air Environment high enough because such furnace filters capture large and microparticles, it may eventually cost you a lot in repair and replacement costs.

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