What MERV 11 means for an HVAC filter

MERV 11 is a particle-filtration classification. It describes performance under a standard test. It does not, on its own, establish gas-removal efficiency, antiviral action or a guaranteed reduction of pollutants in an occupied room.

What the MERV rating measures

MERV stands for Minimum Efficiency Reporting Value. The rating compares particle capture in defined size bands using an ASHRAE test method. The EPA’s MERV table lists three efficiency bands for MERV 11. These are classification thresholds, not a promise that every room will achieve the same air quality. Source: EPA MERV guidance.

What the PURITY TECH report states

Laboratory report 26/014, dated 4 March 2026, classifies the tested PURITY TECH sample as MERV 11 at 830 cfm. The specimen measured 560 × 560 mm, with an effective media area of 0.31 m². The classification belongs with these test conditions, rather than being treated as a result measured in a customer’s building.

The report expressly limits its results to the tested sample and condition. It also says that the results cannot by themselves quantitatively predict performance in all real-life environments. Read the complete ASHRAE test report, including its measurement conditions and uncertainty information.

Particle filtration and textile treatment are different tests

A MERV classification describes particles, not a general percentage for removing odours or gases. Product claims about antiviral treatment require their own test method and conditions. Keep these evidence streams separate when comparing products. The EPA guide to air cleaners also distinguishes filters intended for particles from those intended for gases.

Check the system as well as the filter

Before an upgrade, review fit, mounting, airflow and maintenance with the installer. A test on a sample is not a guarantee of zero pressure drop or unrestricted compatibility with every air-conditioning unit. Filtration also complements, rather than replaces, source control and appropriate ventilation. EPA guidance on filtration and indoor air explains this broader approach.

Questions to ask before choosing

• Which test report supports the stated classification, and at what airflow?
• Does the proposed media fit securely without gaps or interference?
• Which performance claims concern particle capture, textile treatment or personal perception?
• What installation and maintenance checks are required for this system?

Explore the technical documents, review the installation overview, or discuss your application with PURITY TECH.