Delos Special Report: A HEPA Filter Does Not Guarantee HEPA Efficiency Outcomes in Portable Air Purifiers

Sep 2, 2021 4:45 PM ET

NEW YORK, September 2, 2021 – There is a common misconception that all air purification devices that utilize a HEPA filter (a pleated mechanical high-efficiency air filter that goes inside an air purification device) achieve the HEPA benchmark for filtration efficiency when operating in a real-world environment. However, there is a clear distinction between a HEPA filter in isolation versus an air purification device that meets or exceeds HEPA filtration efficiency outcomes. 

Delos, a wellness real-estate and technology company, commissioned LMS Technologies, Inc., an independent, accredited laboratory to test five readily available consumer air purification devices with a HEPA filter inside them. The data showed that total device output for all five air purifiers when operating was less efficient than the 99.97% HEPA benchmark, with results as low as 81.83%. This means that tens to hundreds of thousands of particles were not captured by these devices. Only the Intellipure Compact, which also was tested by the same laboratory, met, and in fact exceeded, the HEPA benchmark.

EN-1822 MPPS Test Results:

Air Purification Device

Particle Efficiency at 0.3 Micron 

Particles Not Captured

Intellipure Compact 



HEPA Device #1



HEPA Device #2



HEPA Device #3



HEPA Device #4



HEPA Device #5



“In a real-world setting, particularly with a pathogen concern, what matters most is the performance of the device in its entirety, not a rating applied to the filter within the device,” said Paul Scialla, Founder and CEO of Delos. “There are multiple factors that contribute to the efficiency of an air purifier, including manufacturing quality and air flow rates. As a result, we do not rely on the HEPA filter rating alone in vetting and validating air purification devices, but also consider filtration efficiency outcomes.”

Delos leveraged four years of research examining ultra-fine particle filtration, including a review of over 100 different air quality devices and technologies, in making its comprehensive, evidence-based recommendation of the Intellipure Compact for education, corporate, hospitality, senior living, retail and other facilities in the U.S. and abroad, including New York City, Miami-Dade, Portland and Chicago public schools.

Delos advises anyone in the market for an air purification solution to consider the unit’s total device efficiency before making a purchasing decision. Far too many devices with HEPA filters do not achieve HEPA filtration efficiency outcomes when measuring the actual unit’s performance in its entirety, rather than just the filter inside.

About Delos

Delos is a wellness real estate and technology company guided by the mission to be the world’s leading catalyst for improving the health and well-being of people around the world by improving the indoor environments where they live, work, sleep and play.  Informed by more than eight years of research and rigorous analysis of environmental health impacts on people, Delos and its subsidiaries offer an array of evidence-based technology and solutions for residential, commercial and hospitality spaces. Delos is the founder of the WELL Building Standard™, the premier standard for buildings, interior spaces and communities seeking to implement, validate and measure features that support and advance human health and wellness. Its subsidiary, the International WELL Building Institute, administers and continues WELL’s development and drives market adoption. Delos’ advisory board is comprised of leading professionals across real estate, government policy, medicine and sustainability.

For more information about Delos, please visit