MERV and HEPA are separate rating systems: MERV grades general ventilation filters from 1 to 16 under ASHRAE Standard 52.2, while HEPA is a high-efficiency class that must capture at least 99.97% of 0.3 µm particles under the U.S. definition.
A MERV rating shows a filter's minimum capture efficiency in three particle-size ranges between 0.3 and 10 µm. ASHRAE Standard 52.2 tests Range 1 (0.3–1 µm), Range 2 (1–3 µm) and Range 3 (3–10 µm). MERV 13 requires at least 50% efficiency in Range 1, while MERV 16 requires at least 95%.
We explain how these ratings shape media selection in how MERV ratings affect high-efficiency filter media selection.
In the U.S., a HEPA filter must remove at least 99.97% of particles 0.3 µm in diameter, as defined by the Department of Energy. The EPA describes 0.3 µm as the most penetrating particle size (MPPS) for this definition, so larger and smaller particles are captured with even higher efficiency.
EN 1822 provides the European classification framework for high-efficiency filters, while ISO 29463 provides an international framework for testing and classifying high-efficiency particulate air filters; both test at the filter's own MPPS. Under EN 1822, H13 requires 99.95% and H14 requires 99.995% integral efficiency, while the E10–E12 classes sit between general ventilation filters and HEPA.
You may also see HEPA described as MERV 17–20, including in an EPA technical bulletin. These values do not come from the standard ASHRAE 52.2 test, which defines MERV 1 to MERV 16 only; the standard's informative appendix notes that HEPA and ULPA filters were assigned such values based on IEST standards. A 52.2 test alone cannot rate a filter above MERV 16.
MERV 13 and MERV 16 are high-efficiency general ventilation filters, while HEPA classes capture nearly all particles at the most penetrating size. The chart below compares their minimum requirements.
| Filter class | Standard | Minimum efficiency | Measured at | Position |
|---|---|---|---|---|
| MERV 13 | ASHRAE 52.2 | 50% | 0.3–1 µm | High-efficiency general ventilation |
| MERV 16 | ASHRAE 52.2 | 95% | 0.3–1 µm | Top of the MERV scale |
| E12 | EN 1822 | 99.5% | MPPS | Highest E class, one step below HEPA |
| H13 | EN 1822 | 99.95% | MPPS | Entry HEPA class |
| H14 | EN 1822 | 99.995% | MPPS | Higher HEPA class |
| HEPA (U.S.) | DOE definition | 99.97% | 0.3 µm | U.S. HEPA benchmark |
Because the test methods differ, cross-standard comparisons are approximate. The WHO's filter comparison table, for example, places MERV 16 alongside the E10 class, well below H13.
Only if the system is designed for it, because HEPA filters add pressure drop that many existing HVAC fans cannot overcome. NIOSH notes that many light-commercial and rooftop package units lack the fan capacity for higher-efficiency filters and may then fail to deliver their designed air volume.
The EPA advises using the highest-rated filter that the system fan and filter slot can accommodate, and notes that ducts and filter boxes may need to be resized for higher-efficiency filters. HEPA filters also rely on very deep pleats, so housing depth matters. Before upgrading, check:
Sealing is critical. NIOSH ties HEPA performance to the absence of leakage around the filter, and the EPA recommends checking filter fit to minimize bypass.
Choose the filter class that meets your particle-control target within your system's airflow and pressure limits. Reference points from recognized bodies include:
Between these levels, the media matters. Hifyber supplies multilayer nanofiber HVAC filter media to filter manufacturers in classes from MERV 8 to MERV 16, while its product literature also lists legacy F7 through E12 classifications; a finished filter's rating still depends on how the media is converted and tested. The company describes the media as relying on mechanical rather than electrostatic filtration and references ASHRAE 52.2 Appendix J as a conditioning procedure. It also reports lower pressure drop than glass-fiber media and notes that filter designs using it can reach an A+ Eurovent 4/21 energy rating. See why low pressure drop HVAC filters matter and Hifyber's HVAC filter media.
No. MERV 13 requires at least 50% efficiency for 0.3–1 µm particles, while a U.S. HEPA filter must capture at least 99.97% of 0.3 µm particles.
No. MERV 16 is the highest class on the MERV 1–16 scale and requires at least 95% efficiency in the 0.3–1 µm range. HEPA follows separate requirements, such as 99.97% at 0.3 µm in the U.S. or H13 and above under EN 1822, so the two are not interchangeable.
Not within the standard test. ASHRAE 52.2 defines MERV 1 to MERV 16; higher values sometimes quoted for HEPA and ULPA filters were assigned from IEST standards.
Under EN 1822, H13 must reach 99.95% efficiency at the most penetrating particle size and H14 must reach 99.995%, so H14 lets through ten times fewer particles.
Not by itself. ASHRAE notes that air-cleaner effectiveness depends on filter efficiency, the amount of air filtered and the path the clean air follows.
Not sure which media, efficiency class or pressure-drop target fits your system? Tell us about your application and get your filtration assessment from Hifyber's team. You can also explore Hifyber's nanofiber HVAC filter media.
