Does a Higher MERV Rating Restrict Air Flow?

Learn how a higher MERV rating affects airflow in your HVAC system and how to choose an appropriate filter for your home.

Does a Higher MERV Rating Restrict Air Flow?

A higher MERV rating can mean greater resistance, which can lead to less airflow. This is an important factor to consider when researching HVAC systems, as airflow is essential for the performance and longevity of your oven or air handler, as well as for a comfortable home. In most cases, a filter with a higher MERV rating will reduce airflow. However, other factors such as the size of the filter and the type of fan motor of the HVAC system can also play a role.

Generally speaking, modern HVAC systems have no problem working with higher MERV filters, so many homeowners rely on them. The main risk of high-efficiency air filters comes from not changing them regularly. If you are aware of when to change your filters, you are unlikely to experience any issues with your HVAC system. Using an air filter with a MERV rating that is too high is just as bad as using one that is too low.

Air filters with higher MERV ratings may filter more, but the thickness of the filter material may restrict airflow. Restricted airflow can decrease comfort, increase energy use, and accelerate wear of HVAC components. In particular, using an air filter with a too high MERV rating can damage the compressor, heat exchanger, and air conditioner coil. A MERV rating is a good indicator of the effectiveness of an air filter in your central HVAC split system; the higher the rating, the better the filter.

As the MERV rating increases, fewer pollutants and dust pass through the filter, making the incoming airflow of better quality. The AC coil inside or near your furnace or air handler gets very cold as it draws heat out of the space and pumps it out. A normal flow of warm air over the coil will prevent its surface from falling below 32°F. Low airflow allows coil to freeze cool.

Then the moisture in the air freezes and the coil is covered with ice. At that time, the air conditioning system can't do its job. The goal of using a MERV 12 filter or higher is a better IAQ: cleaner, more breathable air for everyone, and especially for those with allergies, asthma, COPD, etc. If you are in a situation where you should not use a high MERV (12+) filter for your oven or air conditioner and would like to research air purifiers, here are two suggestions. MERV 11 air filters are slightly more expensive than standard filters but are usually worth it for their added efficiency.

Since air filters in many residential homes contribute more than half of that pressure, it is clear that they are responsible for much of the pressure drop in an HVAC system. The same applies to households with smokers or pets; MERV 11 air filters better eliminate odors. MERV 8 air filters are almost as affordable as less efficient products, making them good value for money. Meanwhile, air filters with a MERV rating of 14 or higher are designed for commercial HVAC systems that can handle coarser filter material. Provides expert knowledge on a myriad of home air filtration topics, including HVAC filters, filtration efficiency and indoor air quality. To further improve indoor air quality, household air purifiers employing HEPA (High Efficiency Particulate Air) filters can theoretically remove 99.97 percent of mold, pollen, bacteria and other particles as small as 0.3 microns according to U.Since using an air filter is not optional, you'll need to find one that meets your needs in terms of both filtration and airflow.

An air filter with a higher MERV rating can block microscopic particles such as smoke molecules due to its tighter mesh fabric.