Filtration Technology

MERV vs HEPA: Which Filter Rating Do You Need?

MERV and HEPA measure filtration on different scales for different products. Confusing them leads to the wrong spec — here is how they relate, with the standards behind each.

By the LYL Clean Air Engineering Team · Published Jul 4, 2026 · Updated Aug 10, 2026

Quick answer MERV (Minimum Efficiency Reporting Value) is the ASHRAE 52.2 scale used for general ventilation filters and reports efficiency across particle-size ranges from 0.3 to 10 microns. HEPA is a separate classification: the US EPA reference value is at least 99.97% capture at 0.3 microns. Do not convert MERV to HEPA one-to-one. For sourcing, request the exact filter report, sealing design and whole-device CADR rather than relying on the label alone.

Chart: EPA lists MERV 13 at 50% or more for 0.3 to 1.0 micron particles, while HEPA captures at least 99.97% at 0.3 micron — MERV and HEPA are separate filter rating systems; neither value is a whole-device CADR.

Buyers often ask a factory for "a MERV 13 air purifier" or "a HEPA HVAC filter" — mixing two rating systems built for different products. Getting this right protects both your spec and your marketing claims.

MERV vs HEPA, Side by Side

	MERV	HEPA
Standard	ASHRAE 52.2 (since 1987)	EN 1822 (EU) / US HEPA spec
Scale	MERV 1–16	H11–H14 (EN 1822); above MERV 16
Efficiency reference	MERV 13 ≥50% at 0.3–1.0µm	HEPA ≥99.97% at 0.3µm
Typical use	HVAC, in-duct, building systems	Standalone air purifiers, cleanrooms, medical
Buyer expectation	HVAC contractors, facilities	Retail / Amazon shoppers expect the HEPA label

Sources: US EPA — MERV ratings; ANSI/ASHRAE 52.2 testing.

How Close Is MERV 13 to HEPA?

No. The current US EPA MERV table lists MERV 13 at ≥50% for 0.3–1.0 µm, ≥85% for 1.0–3.0 µm and ≥90% for 3.0–10 µm. HEPA is a separate classification with a reference value of at least 99.97% at 0.3 µm. In a real unit, airflow, bypass leakage and filter loading determine how those filter ratings translate into delivered clean air.

What This Means for Your Product

For a standalone air purifier, specify the filter class supported by the exact filter report and verify the assembled unit's CADR. MERV normally applies to general ventilation filters. Under EN 1822 terminology, E10–E12 are EPA classes and H13–H14 are HEPA classes; do not market an E11 filter as H11 HEPA. Match every carton and listing claim to the document set for that SKU and target market.

Sourcing a HEPA air purifier line?

Tell us your target market and we will recommend the HEPA grade and configuration, with the test reports to back the claim.

Request Model Options

Comparing in-duct filtration against a room unit? See whole-house vs portable air purifier.

Related Guides

Corsi-Rosenthal box vs commercial purifier — MERV-13 physics in action.
HEPA H13 vs H14 — choosing within the HEPA grades.
Ionizer vs HEPA — and the ozone question.
Verifying HEPA quality — documents to request.
Air purifier models — browse the OEM/ODM range.

General sourcing information. Confirm filter grade and test method against the SKU test report.

Buyer FAQ

Frequently Asked Questions

What is the difference between MERV and HEPA?

MERV is the ASHRAE 52.2 scale used for general ventilation filters and reports efficiency across particle-size ranges from 0.3 to 10 microns. HEPA is a separate filter classification; the US EPA reference value is at least 99.97 percent capture at 0.3 micron. The two systems should not be converted one-to-one.

Is MERV 13 as good as HEPA?

No. The US EPA lists MERV 13 at 50 percent or more capture for 0.3 to 1.0 micron particles, 85 percent or more for 1.0 to 3.0 microns and 90 percent or more for 3.0 to 10 microns. HEPA is a separate classification with at least 99.97 percent capture at 0.3 micron. Whole-device performance also depends on airflow and leakage.

Should an OEM air purifier use MERV or HEPA?

Use the rating system that matches the product and market claim. MERV normally applies to general ventilation filters, while portable purifiers may specify an E-class or H-class filter under EN 1822. Request the filter test report, sealing design and whole-device CADR for the exact model instead of relying on a label alone.

Related reference: the air purifier glossary defines MERV, HEPA grades and MPPS side by side.