What’s the Difference Between MERV and HEPA Filters?

person replacing HVAC air filter in ceiling

According to the Environmental Protection Agency (EPA), the average American spends 90% of their time inside, so it’s important for our health and our families' health to ensure that our indoor air quality is as high as possible.

One thing that has a significant impact on indoor air quality is your HVAC and air filtration system. When it’s time to replace an air filter, there are scores of models. Having so many options can make it hard to know which is right for your home. Learn about the difference between HEPA and MERV filters and which to choose for your home.

What are HEPA Filters?

HEPA filters are High-Efficiency Particulate Air filters that eliminate microscopic air pollutants (99.7% of contaminants between 0.3 and 10 microns), including viruses and bacteria. They were originally used primarily in hospitals and other medical facilities, but HEPA-filtered air is becoming more common in commercial and residential structures as well.

How Long Do HEPA Filters Last?

Wondering when to replace your HEPA filter? The best practice is to check the filter every 3-6 months to see if it needs cleaning or replacement. A filter with damage—either from heavy cleaning or natural wear—needs to be replaced to maintain optimal indoor air quality.

What Are MERV Ratings on Air Filters?

MERV is an acronym that stands for Minimum Efficiency Rating Value, which is a scale to measure the effectiveness of air filters. The MERV rating scale was developed by the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) to help homeowners understand how compatible a filter is with their furnace, as well as how much protection it offers to their families.

  • An air filter’s MERV rating is based on the number of particles the filter can effectively remove from the air. There are MERV filter ratings from 1-16. The higher the number, the smaller the particles it can filter.
  • The EPA advises using a filter with a MERV rating of 13, which can reduce 75% or more bacteria-sized pollutants from the air.
  • Select the right size filter for your system. A filter that is too large or too small won’t be as effective as a properly sized filter.

What Is the Difference Between HEPA and MERV Filters?

HEPA filters are highly effective at removing small particles from the air, including viruses and bacteria. A HEPA filter exceeds even the highest-level MERV filter in terms of both how many particles it filters and how small those particles can be. A MERV 16 filter, which is the highest rating, can filter up to 95% of particles that are 0.3 microns in size, while a HEPA filter can filter 99.97% of those particles.

Indoor Air Quality Questions? We Can Help!

If you have questions or concerns about your home’s indoor air quality, the pros at Allen’s are here to help! With over 60 years of experience assisting Kentucky homeowners with their HVAC needs, we have the skills and knowledge to help you keep your home safe and comfortable. Call us at (270) 946-1525 or schedule service online.