Important Updates to ASHRAE’s Ventilation Standard 62.1 Make it Easier to Design & Operate Buildings Safely and Energy Efficiently

Published 02/16/2022
ASHRAE Addendum aa

New Addendum aa removes barrier to widespread adoption of ASHRAE’s IAQ Procedure, paving the way for building emissions reductions and cost savings

Note: In September 2022 ASHRAE published a new and expanded version of ASHRAE Standard 62.1 (Standard 62.1-2022) that incorporated the updates described below that were previously published as Addendum aa to Standard 62.1-2019. All the updates described in this press release are now part of Standard 62.1-2022.

Westwood, MA – Feb. 16, 2022 – enVerid Systems, the leading provider of sustainable indoor air quality solutions, commends ASHRAE for publishing Addendum aa to Standard 62.1-2019, Ventilation for Acceptable Indoor Air Quality. Addendum aa removes the largest barrier to using ASHRAE’s IAQ Procedure (IAQP) to improve building energy efficiency and indoor air quality: the complexity of applying the IAQP. With the dual priorities of ensuring healthy indoor air and the need for energy efficient buildings to reduce carbon emissions, Addendum aa is expected to accelerate adoption of a key provision of the existing building ventilation standard that can accomplish both goals.

Standard 62.1, the ASHRAE standard that addresses ventilation for acceptable indoor air quality (IAQ) for commercial and industrial buildings, permits two procedures for calculating mechanical ventilation rates: the Ventilation Rate Procedure (VRP) and the IAQ Procedure (IAQP). The VRP and the IAQP are equally valid bases for design under the standard, but most HVAC systems in non-residential buildings have been designed using the less efficient VRP because it is a prescriptive path that ismore straightforward for HVAC system designers and operators to apply. Now with Addendum aa, using the more energy efficient IAQP is as easy to apply as the VRP, bringing the important benefits of improved IAQ and lower energy use intensity within easy reach.

“Addendum aa is game-changing and will drive adoption of the IAQP for healthy and efficient buildings,” said Cory Duggin, Principal and Energy Project Engineer at TLC Engineering Solutions, one of the largest mechanical, electrical and plumbing (MEP) firms in the U.S. “Addendum aa removes the complexity of applying the IAQP by adding more clarity and specificity to the calculation, making it as easy to apply as the VRP while delivering better IAQ more energy efficiently. We have successfully used the IAQP with sorbent air cleaning on numerous projects, including the award-winning Southwest Florida Community Foundation Collaboratory adaptive reuse design, which received the first LEED Gold Certification using the U.S. Green Building Council’s new indoor air quality pilot credit. With the publication of Addendum aa, we look forward to using the IAQP on many more projects in the future.”

ASHRAE Standard 62.1-2019 Addendum aa

Removing Barriers to Adoption

A major barrier to the adoption of the IAQP was the requirement for HVAC engineers to identify Design Compounds, formerly called contaminants of concern, and appropriate limits for each contaminant. Addendum aa addresses this by prescribing fourteen Design Compounds plus PM2.5 that must be controlled when using the IAQP. Addendum aa also prescribes Design Limits for each compound and PM2.5.

Read more about Addendum aa on our blog.

Daikin Applied recently introduced the upgraded Rebel Applied™ with enVerid Sorbent Ventilation Technology™ (SVT™), the industry’s first IAQP compliant packaged total-air-quality system that combines the benefits of sorbent media with a class-leading, configurable rooftop unit.

“As we enter our ‘new normal’ with a heightened focus on IAQ and decarbonization, the IAQP is key to advancing air quality, and trimming energy use and emissions at the same time,” said Jim Macosko, vice president of product management at Daikin Applied. “With Addendum aa, HVAC designers should now embrace the IAQP as a best practice for achieving sustainable IAQ. The timing could not be better with the recent passage of the Bipartisan Infrastructure Deal, which includes significant funding for improving IAQ and energy efficiency in buildings.”

enVerid, Daikin Applied, and other suppliers of air cleaning systems have developed IAQP calculators that make it easy for engineers to comply with Addendum aa with the click of a few buttons.

Improving Indoor Air Quality & Safety

For many buildings, the most cost effective and energy efficient way to implement ASHRAE’s latest COVID-19 guidelines is to use IAQP ventilation rates with MERV 13 or higher particle filters to capture bioaerosols and sorbent filters to capture gaseous contaminants.

Updated in October 2021, ASHRAE’s Core Recommendations for Reducing Airborne Infectious Aerosol Exposure are based on the concept that ventilation, filtration, and air cleaners can be deployed flexibly to achieve exposure reduction goals while minimizing the energy penalty from increased outside air.

ASHRAE’s Core Recommendations advise maintaining at least required minimum outdoor airflow rates for ventilation as specified by applicable codes and standards such as ASHRAE Standard 62.1, using combinations of filters and air cleaners that achieve MERV 13 or better levels of performance for recirculated air, and selecting control options, including filters and air cleaners, that provide desired exposure reduction while minimizing associated energy penalties. Read more about the Core Recommendations in our blog.

Reducing Building Emissions

It has not always been easy to deliver excellent IAQ without wasting energy. “Historically, there has been a tug of war between indoor air quality and energy efficiency,” said Drew Morrison, an energy engineer with Slipstream, an independent nonprofit organization focused on accelerating climate solutions for everyone. “The building world has long considered these objectives to be mutually exclusive, but by combining sorbent air cleaning systems with the IAQP, cleaned indoor air can substitute for outdoor air ventilation leading to energy savings and good indoor air quality.”

“The IAQP is more energy efficient and cost-effective than the VRP because it allows for the use of air cleaning when calculating ventilation rates,” said Christian Weeks, CEO of enVerid Systems. “Under the IAQP, filtered indoor air can offset a portion of the outside air requirement to achieve a more cost effective, energy efficient design. The VRP relies exclusively on large volumes of hot, humid, and cold outside air to dilute indoor generated contaminants, which requires larger, more expensive HVAC systems and is very energy intensive. Additionally, because the VRP is based on generic contaminant sources and emission rates, it is a less direct way to ensure good indoor air quality, especially for buildings located near permanent or seasonal sources of pollution. With the VRP and the IAQP now on equal footing in terms of implementation, we anticipate a rapid acceleration in the use of the IAQP by HVAC engineers and building owners eager to ensure healthy building environments while also achieving energy efficiency objectives.”

The latest Standard 62.1 User’s Manual was published in June 2021 and details when using the IAQP may be more appropriate than the VRP. Read more about the Users’ Manual and IAQP on our blog.

About enVerid Systems, Inc.

enVerid Systems, the leading provider of sustainable indoor air quality (IAQ) solutions, helps buildings achieve air quality goals, save money and reduce energy consumption and carbon emissions. Its flagship HVAC Load Reduction® (HLR) modules are award-winning air cleaners that deliver up to 40% HVAC energy savings and superior indoor air quality in new and existing buildings. For new HVAC systems, HLR modules also enable immediate capital cost savings. At the core of all HLR modules is enVerid Sorbent Ventilation TechnologyTM (SVTTM), uniquely designed to capture gaseous contaminants that degrade indoor environmental quality. enVerid’s HEPA air filtration products remove particulate and microorganism contamination, including viruses, from indoor air without the significant cost of upgrading mechanical systems and increasing mechanical ventilation rates. enVerid’s products are deployed in commercial, academic, and government buildings globally. Its air cleaning products meet recommendations outlined in ASHRAE Standard 62.1, are LEED® and WELL compliant, and are eligible for utility rebates. For more information, please visit