April 2023
Read Time: 3-4 Minutes
Understanding an Air Filter’s MERV Rating
When selecting an air filter for your home’s HVAC system, it’s important to understand the MERV rating. MERV stands for Minimum Efficiency Reporting Value, which is a measure of how effective an air filter is at capturing airborne particles.
The MERV rating scale ranges between 1 to 20. The higher the MERV rating, the more efficient the filter is at trapping particles. Let’s take a look at the different types of ratings to help you understand which air filter might be best for you.
MERV Ratings 1-4
MERV 1-4 filters provide minimal dust protection, and they must be replaced more frequently than other filters due to their lower efficiency. These filters are not recommended for homes with individuals who suffer from allergies or respiratory issues. These filters may be more affordable, but they do not effectively remove smaller particles from the air.
MERV Ratings 5-8
MERV ratings of 5 to 8 indicate a low to medium-quality filter that is adequate for most homes. They can capture particles as small as 3 microns in size, such as mold spores, animal dander, and dust mite droppings, which are strong triggers for allergy symptoms.
MERV RATINGS 9-12
Filters with a MERV rating of 9-12 are highly effective at removing particles from indoor air that can be hazardous to your health, making them an ideal choice for homes with individuals who have respiratory conditions such as COPD, allergies, and asthma. They can trap particles as small as one micron, including Legionella and humidifier dust. These filters are the best option for residential HVAC systems without requiring serious modifications, providing excellent air filtration for homes.
MERV Ratings 13 and Up
MERV 13-20 filters are highly efficient at removing harmful particles from indoor air, including viruses, bacteria, and carbon dust. Filters with a MERV rating of 16 or higher are considered hospital-grade. However, residential applications of MERV 16 filters have grown significantly in popularity after the COVID-19 pandemic.
Lennox offers one of the best MERV 16 filters on the market for residential applications. These filters capture more than 95% of particles down to .3 microns including viruses and bacteria.
Safely Using a MERV 13 or Higher
It’s important to understand if your home’s equipment can handle using a MERV 13 or higher. While higher MERV-rated filters can provide better air quality, they can also put additional strain on your HVAC system. Filters with a MERV rating of 13 or higher may restrict air flow, reducing the efficiency of your HVAC system and potentially causing damage.
If you need help determining if your existing equipment can utilize a high MERV rating filter, give our office a call. We’re happy to help.
MERV Rating Frequently Asked Questions (FAQ)
Some filters capture particulate matter as small as 1 micron, so how small is a micron?
A micron is one-millionth of a meter or 1/25,400th of an inch. It is a very small unit of measurement, and can be difficult to visualize. The naked eye can see objects as small as 25 – 40 microns. That’s quite small considering a 1″ postage stamp is 25,400 microns. Here are a few more examples to help put it into perspective:
Image Source: https://www.weforum.org/agenda/2020/10/covid-19-coronavirus-disease-size-compairson-zika-health-air-pollution/ 
What is the most common MERV rating?
The most common MERV rating for residential homes in the US is MERV 8-11. This range is effective at capturing larger particles such as pollen, dust, and pet dander, but may not be as effective at capturing smaller particles such as bacteria and viruses.
However, many homes can benefit from a higher MERV rating, such as MERV 13 or MERV 16 filter, which can provide better air filtration and improved indoor air quality. If you are considering upgrading your filter to a higher MERV rating, it’s important to consult with a professional HVAC technician to determine the best MERV rating for your home’s HVAC system.
Why do big box stores use a different rating system?
Big box stores often use rating systems for air filters that differ from the MERV rating system. Instead, they might use scales like the MPR developed by 3M or the FPR developed by Home Depot. While these scales typically measure similar factors as MERV, they have different ranges.
The MERV rating system is widely considered superior because it is an internationally recognized standard. Using the MERV rating system makes it easier for consumers to compare filters across different brands.
Can all HVAC systems handle a MERV 13 or higher rating?
Not all HVAC systems can handle a MERV 13 filter, so it’s essential to check with a professional before making any changes to your system’s filter cabinet.
Are higher MERV-rated filters always better?
While higher MERV-rated filters can provide better air quality, they can also put additional strain on your HVAC system. Energy use can also increase as your system will need to work harder to move air throughout your ductwork. It’s important to consult with a professional HVAC technician to determine if your equipment can safely handle a higher MERV-rated filter.
In conclusion, selecting the right MERV rating for your home’s air filter is critical for maintaining indoor air quality and the efficiency of your HVAC system. By understanding the MERV rating system, consulting with a professional, and selecting the right filter, you can ensure that your home’s air is as clean, healthy, and comfortable as possible.
Is it time to replace your filter? With our online store, replacing your filter is more convenient than ever!
