Everything You Need to Know About MERV Rating

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MERV ratings are important for the health of your home. Find out everything you need to know about MERV rating.

Everything you need to know about MERV Rating 

Everything You Need to Know About MERV Rating

Air filters are a critical component of your HVAC system as they keep dust, allergens, and other airborne pollutants out of your home. They play a crucial role in the efficient functioning of your HVAC system and indoor air quality. Every time you change your system’s air filter, you are doing it and yourself a big favor, as it will improve its lifespan and minimize the need for costly repairs. Regularly replacing an air filter as directed will ensure cleaner, fresher, healthier air for everyone in your home.  

What is MERV?

Not all filters are created equal. The MERV rating is the key determinant of the effectiveness of an HVAC air filter and has several important implications. MERV refers to “Minimum Efficiency Reporting Value” and the MERV rating measures how effectively an air filter can remove particles from the air that passes through it. The higher the MERV rating, the more contaminants the filter will capture, leading to healthier indoor air quality. As mentioned at, the value helps compare the performance of air filters in filtering out dust particles and other pollutants. It is derived from a testing method designed by ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers).

MERV Rating and Efficiency

MERV rating ranges from 1-20. As mentioned, the higher the MERV rating on the filter, the fewer dust particles, and other contaminants can pass through it and enter the air stream. Here is a quick look at the MERV rating scale to understand which filters are apt for which applications.

MERV 1-4

With the lowest level of filtration, this type of air filter is commonly used to pre-filter commercial buildings, and for residential furnaces and window air conditioners. It filters pollen, dust mites, sanding dust, and textile carpet fibers.

MERV 5-8

As the bare minimum for efficiency, they are used for commercial and residential buildings; however, they are not the most effective at trapping large portions of airborne particles. With that said, they can filter pollen, dust mites, sawdust, textile and carpet fibers, mold spores, dust and lint, and cement dust. It is recommended that every home uses filters that have a bare minimum MERV rating of 8.

MERV 9-12

Air filters with this rating provide above-average air quality and may be used in hospital laboratories in addition to commercial and residential spaces. They are effective at controlling humidifier dust, lead dust, auto emissions, and coal dust.

MERV 13 and Higher

Providing heavy-duty air filtration, they are incredibly efficient at filtering all of the contaminants listed for MERV 1-12 above, with the addition of bacteria, dust from smoke, automobile fumes, saliva droplets, and insecticide dust. Filters with a MERV rating above 13 are quite restrictive, usually used for labs, hospitals, surgical operating rooms, and other contexts that require absolute cleanliness.


Choosing the Correct MERV Rating

Many homeowners do not pay heed to the MERV rating when buying an air filter, but there are various factors you must consider to choose the right HVAC filter for your home. Does anyone in your home suffer from a respiratory condition?  Do you have pets? How often do you keep your doors and windows open? Are you a smoker?


Residences do not generally need filters higher than MERV 8 as it removes most of the contaminants from your indoor air. These air filters are ideal for standard homes and businesses and are the perfect choice for people who do not have allergies or other health issues. Opting for a cheaper, less effective filter can prove to be a risk for your family and HVAC system. However, if you have pets or someone in your home has a medical condition, asthma, or allergies that make it difficult for them to breathe, it will be beneficial for you to get a high-rated filter with MERV 9-12 rating. The more highly rated the filter, the cleaner the air, making it easier to breathe.


With that said, it is important to note that when choosing an AC filter for your home, a higher MERV rating is not always better. Air filters with a MERV rating of above 13 will efficiently remove the harmful contaminants from your home but restrict airflow as they have smaller pores to capture the tiny particles. That can put too much pressure on the fan of your HVAC system and other components and impair its performance if it is not designed to manage this resistance, as well as worsen indoor air quality. Besides, choosing a filter with a rating too high could raise your utility bills too.


When you are trying out to find the perfect air filter for your home’s HVAC system, you will notice a MERV rating attached to almost every brand’s air filter. Changing an air filter can significantly elevate the quality of the air you breathe in your home. However, you must ensure to choose an air filter with a MERV rating that best suits your requirements, which will be determined by a range of factors as explained.


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