Real World Recommendations for Cleaner Indoor Air

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If the last few years have taught us anything, it’s that good indoor air quality (IAQ) isn’t just a “nice to have” – it’s a must have. From allergens to infectious diseases, indoor air carries a lot more than what meets the eye. We talked with Eric Haley—a Baskervill Principal and mechanical engineer—about the work the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) Epidemic Task Force recently completed to provide easy to understand recommendations for building owners.  

ASHRAE’s task forces, made up of engineers and scientists from across the country, began examining indoor air long before most of the population even understood what it meant. “People are our biggest asset,” says Eric, a professional engineer and certified energy manager who sits on the Epidemic Task Force established in March 2020. “How are we caring for them?”  

Photo showing various buildings with lots of windows.

The reality is: long before COVID, many buildings were sick. (Which meant, many of the people who lived, worked, and recreated in those buildings? Also, sick.) Depending on the age, capability, and overall performance of the building’s HVAC system, it’s been calculated that as much as 3-4% of the air in a space is direct emissions from another person’s lungs. Dubbed “respiratory backwash,” the concept isn’t new but takes on a whole different level of alarm when viewed with the lens of an ongoing worldwide pandemic.  

So, if you own or operate a building, and want to make its air as safe and clean as possible, how do you do it?  

“First, it’s important to know that no amount of building equipment or filtration is capable of eliminating risk entirely,” Eric says. “We’re aiming to reduce risk where we can and assess the most impactful improvements you can make for the investment. Contrary to anecdotal logic, suggestions to ‘just open the windows’ doesn’t quite cut it.”  

Improved ventilation or increasing the rate of outdoor air in a space either through open windows or enhanced air through your HVAC, has been proven to be effective in increasing IAQ. However, open windows put an increased demand on systems—increasing humidity and creating inconsistencies in indoor temperatures—that ultimately decrease its overall efficiency and performance, increasing costs. Cranking up the ventilation via the HVAC is also ill-advised, as it leads to the same efficiency and performance concerns. Eric says Task Force members agreed: to make increased ventilation most effective, systems need energy recovery installed. Energy recovery safely transfers energy from the air leaving the space back into the system, creating energy and utility savings all the while.  

Keep your filters clean. HEPA filters are great but can significantly stress an existing system and are only impactful if they are able to capture particulates. For effective filtration you want to be using at least MERV-13 filters, which are 85% effective at capturing particulates 1-3 microns in size, and clean and replace filters in accordance with manufacturer instructions.  

Consider ductwork and distribution changes based on the long-term risks of your space. Can you separate riskier spaces or create segregated air systems to service specific areas of concern instead of making all-encompassing changes to your entire space? 

Employ a multi-faceted approach which dilutes potential concerns and enhances ventilation. “Overall, this is ASHRAE’s most sound and cost-effective recommendation,” Eric says. 

  • Part 1: Disinfect surfaces so there is less potential for germs and pollutants to become airborne  
  • Part 2: Utilize an off-hours or nighttime flush of ventilation via your existing HVAC to move more (clean) air through the space, creating better air quality during its on-hours use. 
  • Bonus: Add energy recovery to that HVAC for maximum energy savings results. 

The bottom line: better indoor air quality is better for everyone. Interested in exploring how to integrate energy recovery or analyze the best way to improve your IAQ with an existing system? Let’s talk. 


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