Energy efficiency in commercial real estate has become increasingly important over the past few decades. Not only does this practice save money and energy by requiring more efficient air handler systems; it also improves the experience of the people occupying offices, schools, and other buildings. While an energy crisis caused an increase in efficient design and infrastructure retrofitting, a global pandemic forced us to look at indoor air quality (IAQ) in a different way. With a virus spread mostly through indoor air, we realized that the emphases on efficiency had historically surpassed the importance of health and fresh air.  Does it have to be a tradeoff, or can a building have fresh, clean air while remaining energy efficient?

Standards of Indoor Air Quality

To allow updated heating, ventilation, and air conditioning (HVAC) systems to operate at optimal levels, walls must be insulated, building envelopes must be sealed, and the entire building must be as airtight as possible. However, even in buildings where energy efficiency and/or green certification is the primary focus, indoor air quality is still a consideration for occupants.

The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) standard 62.1-2022 defines acceptable air quality as “air in which there are no known contaminants at harmful concentrations, as determined by cognizant authorities, and with which a substantial majority (80% or more) of the exposed people do not express dissatisfaction.”  This does not address transmission of infectious disease or pathogens as it relates to indoor air quality standards. As we discovered during the pandemic, open air spaces are the best way to prevent the spread of pathogens and infectious airborne diseases.  But throwing open the windows to let in the fresh air may also let cost savings fly away.

Introducing Sustainable Indoor Air Quality

Sustainable IAQ is the term for attaining healthy, sustainable IAQ in an energy-efficient and cost-effective way.  The basic concepts involve making improvements and adjustments to a buildings’ existing, energy-efficient systems. Implementation can be broken down into four steps:

  1. Define IAQ goals.
  2. Install filtration, cleaning components, and/or fresh air intake designs/modifications.
  3. Install ventilation controls for outside air.
  4. Test, monitor, and maintain IAQ.

Methods involving the installation of air filtration and cleaning technologies can remove contaminants from the air (including pathogens and CO2). In most scenarios, cleaning recycled indoor air is more energy-efficient than cleaning/conditioning new, outside air. Once the existing indoor air is as clean as possible, ventilation controls such as energy recovery systems can make the intake of outside air more effective.

ASHRAE is developing a new standard focusing on reducing the transmission of pathogens using filters and air cleaners. While the immediate focus is on airborne diseases, these methods could also be used for changing climate issues (like smoke from wildfires or pollution).


For building owners and managers looking to improve sustainable IAQ, the first step should be to conduct an indoor air quality survey to determine whether there are existing air quality issues in a facility. Routine assessment should include measurements for temperature, relative humidity, carbon dioxide, carbon monoxide, odors, and/or other organic compounds.  Assessment should be done by a Certified Industrial Hygienist (CIH) in accordance with NIOSH/OSHA/ASHRAE standards. The key to the successful execution and management of a sustainable indoor air quality program is involving a consultant who has comprehensive knowledge of building systems, industrial hygiene, and sustainability practices. With ever changing regulations and standards, an expert consultant can help building owners and operators navigate this process.  Sustainable IAQ practices promote healthy tenants as well as a healthy bottom line.