What is a MERV Rating for Filters?

In the context of the heating and cooling system, MERV stands for Minimum Efficiency Reporting Value, a value that indicates the amount of particles that an air filter is intended to catch. Higher MERV scores catch smaller particles better. To capture as many pollutants as possible, hospitals usually use MERV 16 or higher.

While lower MERV rating filters are less effective overall, they allow more air to pass through the filter, which can help the HVAC system run more efficiently. It is important to have the right combination of the air filter and MERV ranking to satisfy the needs of your home and system.

The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), which developed the MERV rating, recommends filters with MERV ratings of at least 6. The US Department of Energy suggests a MERV 13 minimum. Purchase an Air Purification System with a MERV 16 media filter for the best total solution for your home, and you’ll be set for years.

MERV Ratings for Home Use


Most home filters have a MERV rating ranging from 3 to 8. There are higher MERV scores, but just because a filter has a higher MERV rating doesn’t mean it’s the best option for you. There are two factors to remember regarding the requirements:

A MERV rating of 6 or 8 would suffice if your goal is to remove pollen due to allergies. Purchasing a higher-rated filter is akin to paying for premium gas when your car just needs regular— it’s a waste of money.

Higher MERV filters have more airflow resistance. The filter media has narrower gaps to filter out the smaller particles, which can slow down the airflow and trigger other issues. It’s equivalent to straining noodles through a coffee filter. The noodles will split fine, but the water flow will be excruciatingly slow.

Most residential furnaces are equipped with and work well with, a 1” thick filter that is MERV-rated 3 to 5, or a 4” or 5” thick media type filter that is MERV-rated 6 to 8.  If you wish to try a filter with a MERV rating higher than any of those, we highly urge you to talk with an HVAC expert first to ensure that the filter can operate with your system without triggering any airflow issues.

Bear in mind that higher-MERV filters would need to be changed more often because they “plug up” quicker.

How Filter Size and Thickness Affect Airflow


The amount of airflow is influenced by the length, width, and thickness of the filter. Length and width are obvious, but thickness is a huge factor.  When you stretch out a 1” thick filter and a 4” thick filter out of their frames, you’ll find that the 4” is roughly four times as long as the 1”. That ensures the 4” filter’s filter media has about 400 percent more available area for air to flow into. This allows the air to circulate freely – there is very little constraint.” You’ll also want decent airflow, which is a key factor in your HVAC system’s effectiveness and performance.

Which Filter is Right for Me?

It can be difficult to determine which filter is best for your house. Before you make a decision, you should think about a lot of aspects, like your home’s location, your family’s health, pets, and the kind of system you have. Though low MERV filters are fine for older units, higher-rated air filters can provide cleaner air and better respiratory quality for your family. If you choose to pick a higher MERV rating, there are several advantages to going up to a MERV rating of even just 8, but depending on your family’s personal situation, you could go as high as 13.

If you want to check on your home’s air quality head-on, you might want to consider adjusting the MERV filter rating. It could make a huge difference in how your house feels. Many of us take air quality for granted, but you might be shocked by how much of a difference a higher MERV rating can make.