How does HEPA compare to MERV Ratings?

Air filtration is one of the best ways you can make sure your indoor air stays clean. However, knowing the best way to go can be confusing, because there are two main types of filters that air filtration systems use: MERV and HEPA. To help demystify the subject, we've created a quick guide on these popular filter types.

HEPA Filters

HEPA filters are more popular and commonly found in brick-and-mortar stores. HEPA is short for High-Efficiency Particulate Air filter. As the name suggests, these filters are highly efficient and are designed to catch particulate matter as small as .3 microns in size and do so at a very efficient rate of 99.97% efficacy or better. These kinds of filters are preferred in hospitals and other medical settings because they can capture viruses and bacteria from the air.

MERV Filters

MERV stands for Minimum Efficiency Reporting Value. These kinds of filters are rated solely on the size of the particulate matter they are able to capture from the air. There are many kinds of MERV filters, and each kind is given a MERV rating based on the size of the particulate captured. Efficacy rates also range in MERV filters, with high-end filters capturing around 75% of all particulate for its designated capture size.

Feature	HEPA	MERV (Best)
Particle size captured	As small as 0.3 microns	Varies by rating; best ratings down to ~0.3 microns
Efficiency rate	99.97% or better	Up to ~75% for designated capture size
Common uses	Hospitals, medical settings, allergy/asthma households	Residential and commercial HVAC systems
Airflow restriction	High — requires compatible equipment	Lower — larger filter grid allows easier airflow

MERV and HEPA Compared

While MERV filters work well enough for some general-purpose air filtration functions, HEPA filters are the much better choice because of the small particles they capture and their high efficacy rates. This is especially true when trying to capture viruses, bacteria, and other fine airborne matter. MERV, however, lets air pass through with less resistance because of its larger filter gridding size.

Which Should You Choose?

If anyone in your household suffers from allergies, asthma, or other respiratory conditions, a HEPA filter is the superior choice thanks to its near-perfect capture rate and ability to trap even the finest airborne particles. For general home use without specific health concerns, a high-MERV rated filter (MERV 11–13) provides solid filtration without placing as much strain on your HVAC system. It is important to confirm your HVAC equipment is rated to handle the filter you choose, since denser filters can restrict airflow and reduce system efficiency. When in doubt, a Balanced Comfort technician can recommend the right filter for your home and system.

Here at Balanced Comfort Cooling & Heating, we know how much good indoor air quality means to our Fresno area customers, and that's why indoor air quality and purification systems are one of our specialties. In addition, we specialize in the full range of heating and cooling services such as home energy audits, professional insulation services, and more. We aren't just heating and air service; We're full home climate control experts. For speedy service, preventive maintenance, or information on our special customer financing plans, give us a call today!