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What Does MERV Rating Mean?


If you have ever purchased an air filter for your home’s heating and cooling system, you may have noticed a MERV rating on the box. This may be the most important bit of information about the filter.


What does MERV rating mean? The answer to this question helps determine what the filter will remove from the air in your home and how long it will last.


Unfortunately, it’s not as simple as going out and buying the filter with the largest MERV rating you can find. That could cause severe damage to your HVAC system.


Keep reading to find out everything you need to know about MERV ratings. The information below will help you determine which is the right one for your A/C system so that your home can have the best indoor air quality.


What Does MERV Rating Mean?

MERV stands for “Minimum Efficiency Reporting Value.” This is the measure of the number of airborne particles a filter removes relative to the volume of air passing through it. MERV ratings for residential furnace filters range from MERV 8 to MERV 16.


A MERV rating of 1 – 4 is the lowest end of filtration. It will remove large particles (about 10 microns and above) from the air. This includes dust, pollen, and small fibres. They also will be the cheapest available filter option but will not last as long as other filters. These filters are not recommended for your home’s heating and cooling system.


MERV ratings 5 – 8 may last a bit longer and will filter out smaller particles (down to 3 microns). This includes mould spores, smaller dust particles, and certain aerosol sprays. These filters should be checked and may need to be changed as often as once per month.

MERV ratings 9 – 12 are considered the top end of residential filtration, catching particles as small as 1 micron in size. You also need to change these filters less frequently. Be sure to check your filter regularly and change them when they appear dirty, at the bare minimum they should be replaced once per year.


Filters with a MERV rating of 13 and up are typically only used for commercial purposes in places such as hospitals and surgical facilities. Increasingly people are turning to these higher MERV benchmarks for their homes because of their ability to filter out pet dander, odours from cooking or tobacco smoke, bacteria and even viruses like COVID-19.


What Is a Good Minimum Efficiency Reporting Value?

After “What does MERV rating mean?” your next question may be, “What is the minimum I need for my home?” The answer to this question is complex.


You might assume that the higher the rating, the better? In general, when it comes to removing contaminants, that is true.


Besides going overboard, there is also a danger in using a too-high rating for your system. This puts an undue burden on your furnace, causing it to work harder than it needs. It could even cause serious damage to your system.


Beyond determining your filtration needs based on the categories listed above, it is best to check with a licensed technician at your local HVAC Company. They will be able to determine what is a good MERV rating based on the size of your system.


Find the Right MERV Rating for Your System

Now that you have an answer to the question “What does MERV rating mean?” you can better understand the importance of furnace air filters. It also means you can decide on what MERV level is right for your home.


Aire One Heating & Cooling is your premier choice for heating and cooling services, plus air filters. We can help you determine the most efficient MERV rating for your system, so you can have clean air in your home without putting too much strain on your system. Reach out to us today for a free quote and consultation.

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