Does a Merv 8 Air Filter Restrict Air Flow?

The short answer is yes, but it's not really a problem, except in extreme circumstances. Most modern HVAC systems have no problem working with superior systems, which is why millions of homeowners depend on them. The main risk of high-efficiency air filters comes from the fact that they are not modified for long periods of time. If you keep abreast of changing filters, you are unlikely to experience any filter related issues with your HVAC system.

Using an air filter with a Merv rating that is too high is as bad as using one that is too low. Air filters with higher Merv ratings can filter more, but the thickness of the filter material can restrict airflow. Restricted airflow can decrease comfort, increase energy use, and accelerate wear and tear on HVAC components. In particular, using an air cleaner with a MERV rating that is too high can damage the compressor, heat exchanger, and air conditioner coil.

They also found that airflow in the high MERV filters decreased by 7% and 11% in the two HVAC systems compared to the low MERV filters. Similarly, the medium MERV filters also showed a decrease in airflow relative to the low MERV filters, this time 3% and 8% lower in both systems. Based on the above-mentioned characteristics, a Merv 8 is considered a superior filtration compared to air filters with a lower MERV rating. The higher the MERV rating of a filter, the less dust particles and other contaminants can pass through it. However, older units may not be able to have enough air pressure to force air through a higher efficiency filter.

It is important to keep this in mind, because many homeowners believe the ratio is simply linear, meaning that as filtration efficiency increases, so does the do airflow resistance at the same rate. Air filters that are Merv 13 and above are recommended for those who prioritize air quality and may have to manage asthma, severe allergies, and other similar circumstances. When used in a multi-filter system, pre-filters trap dirt and large particles before air reaches the final filters downstream, removing the smallest particles. Through this site and the trails it led me along, I have learned that two MERV 11 filters can have the same filtering capacity, but one could allow more air to be transferred. One thing to keep in mind is that a MERV 11 air filter may need to be changed a little more frequently than a MERV 8 air filter. To further increase 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 the U.

S. Department of Energy. Although MERV 8 is known to be effective at filtering pollutants such as pollen, dust mites, sawdust, mold spores and air fluff, higher MERV ratings will clean the air even more. Meanwhile, air filters with a MERV 14 rating or higher are designed for commercial HVAC systems that can handle the coarsest filter material. If you're trying to choose between a MERV 8 air filter and a MERV 11 air filter, here's what you need to know: if someone has an allergy or respiratory problem, choose a MERV 11 air filter or even a MERV 13 air filter. The MERV scale is not linear; the difference between a MERV 6 and a MERV 8 is almost double in the percentage of particles captured.