Air Comfort of KY

Understanding the Air Filter MERV Rating

​​If you have ever shopped for an air filter, you may have noticed that they are given a MERV rating. But what does this rating mean, and how will it impact your HVAC system?
Keep reading to find out!

Minimum Efficiency Reporting Value (MERV)

MERV stands for Minimum Efficiency Reporting Value. It measures the effectiveness of air filters in trapping pollutants, pet dander, and other airborne particles. 

The MERV rating system was developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) in the early 1990s as a way to standardize the measurement of air filter performance. Before the development of the MERV rating system, there was no uniform method for comparing the performance of different air filters, which made it difficult for consumers to choose the best air filter for their needs. 

MERV ratings range from 1-20, with higher ratings offering the increased capture of airborne particulates. Typically, most homes and buildings require a minimum MERV 8 rating to keep the majority of contaminants out of the air and out of the HVAC system components.

Click here to download our MERV Rating Chart.

Is a Higher MERV Rating Better?


Air filters with a high MERV rating are an effective way to capture small particles inside your home, such as dust, pollen, and pet dander. The air filter promotes a healthier living environment by reducing airborne pollutants that can cause health problems. Additionally, air filters with a correct MERV rating can help extend the life of your HAVC system by preventing buildup on components and within the air ducts, which can reduce efficiency over time.

However, it is important to note the impact that higher MERV rated filters can have. Higher MERV rating = increased filtration, but with higher filtration comes reduced airflow and higher static pressures within your HVAC system. Reducing airflow too much (i.e. too high a MERV rating) can lead to decreased system efficiency and poor airflow. 

It is best to consult with our service experts before increasing your air filter MERV rating.

Replacing your home’s air filter regularly is essential for achieving the full benefits of a higher MERV rating and should always be done according to manufacturer-suggested schedules.

Which MERV Rating is Best For You?

Most people think you start with what types of particles and contaminants you want to remove from the air, but that is not the case.

The correct place to start is to test the amount of airflow your system generates and use that information to determine the impact an air filter will have on airflow (friction loss). The best way to calculate airflow rate is to have it measured by an Air Comfort of KY professional. Click here for a detailed technical resource to investigate this subject further.

In addition to how much airflow loss your system can tolerate, other factors to consider include duct design, IAQ solutions like air cleaners and sanitizers, (de)humidifiers or ERV/HRV systems. 

Based on this technical information, you can then accurately select the correct air filter MERV rating to meet your indoor air quality (IAQ) needs.

For example, if you’re looking to capture smaller particles such as dust mites and pollen, you will likely want a MERV rating at the higher end of the spectrum or an air sanitization solution. On the other hand, if you live in an area with low amounts of pollutants or if your home is mostly dust-free, then choosing a lower MERV rating or Ionizing Air Cleaner could support your needs.

It is important to pair your IAQ needs with an understanding of your system’s design and operation to select the correct MERV air filter rating. Doing so will ultimately provide greater comfort and save you money in the long run.

Call Air Comfort of KY today to learn more about improving your indoor air quality!

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