©2023 This excerpt taken from the article of the same name which appeared in ASHRAE Journal, vol. 65, no. 9, September 2023.
About the Author
Tom Hartman, P.E., is principal of The Hartman Company in Georgetown, Texas.
The fundamental value of an office building is the work performed by its occupants. The direct workforce costs each year that enable this value are typically as great as the one-time cost of the building’s construction. Designers and equipment manufacturers should regard this overwhelming cost/benefit metric a mandate to develop and apply systems to provide indoor environments that will maximize the opportunity for occupants to perform at their best. This article discusses how exploiting newer features of ASHRAE Standard 55-2020, Thermal Environmental Conditions for Human Occupancy,1 can put the industry on a path to new methods of distributing comfort and fresh air for VAV systems that will result in healthier and more comfortable office buildings. These buildings will be more environmentally attractive to their office workers, more financially beneficial for the tenants and owners, and help the industry meet its decarbonization goals with ultralow energy, occupant-centric office building operations.
Research has found just small variations from an office worker’s thermal comfort preference significantly reduce work performance,2,3 which is generally found in more recent studies to be in the range of about a 2% to 4% reduction in work productivity for each 1°C (1.8°F) from that desired thermal condition.4 And surveys consistently find only about half or less of office building occupants register as satisfied with their workspace thermal environment.5,6 In addition, though evidence is still considered inconsistent, some studies now show that providing a fresher workspace environment with reduced CO2 levels may significantly improve cognitive capacity, which leads to work performance gains that could be even larger than those from improving comfort.7 – 9
Every bit as important in terms of the effect on office work performance is the way modern offices are configured. Open plan office spaces are at times favored because they facilitate the long-standing method of mixing conditioning air with room air and reduce the likelihood of stagnant air areas. But these more open office configurations allow an easy path for pathogen transmission.10 Also, research has found work performance reductions of more than 20% in open offices compared to partitioned private workspaces for work that requires concentration.11 The “awfulness” of open offices is being ever widely expressed—with studies sometimes cited to back up the claim.12
While additional research is needed to better quantify some of these work performance factors and the interaction among them, it can be estimated with some confidence based on published averages for office building occupant density, profit margins and costs along with the performance research cited above that improving thermal comfort satisfaction alone could increase a typical office building’s net financial bottom line with improved work performance by more than $10/ft2 ($108/m2) each year.13 – 16
By including conservative estimates for the effects that better overall conditioning combined with improved workspace layouts could have on all work performance, absenteeism and turnover, the total financial opportunity is easily several times this value for typical offices—a huge financial opportunity for firms that occupy these buildings. While this work performance value metric, along with a focus on occupant satisfaction, has historically been considered only indirectly—if it is considered at all, it may become increasingly important as building owners and tenants look to encourage the return of workers to the office.
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