ASHRAE got a little defensive about an article published in Nature Climate Change that suggested its Standard 55 – Thermal Environmental Conditions for Human Occupancy – specified indoor temperatures that were comfortable for men but were too chilly for many women.
“Keeping building occupants comfortable while minimizing energy use is a balancing act for engineers who design HVAC&R systems and buildings,” says ASHRAE.
The Nature Climate Change article discussed the method used to determine thermal comfort in ANSI/ASHRAE Standard 55, but Bjarne Olesen, Ph.D., a member of the ASHRAE Board of Directors, said, “The interpretation of the authors regarding the basis for Standard 55 is not correct. The part of the standard they are referring to is the use of the PMV/PPD index. This method is taken from an ISO/EN standard 7730, which has existed since 1982. The basic research for establishing comfort criteria for the indoor environment was made with more than 1,000 subjects with equal amount of women and men.
“In the main studies, where they did the same sedentary work and wore the same type of clothing, there were no differences between the preferred temperature for men and women. So the researchers’ finding of a lower metabolic rate for females will not influence the recommended temperatures in the existing standards. Also their study is not conclusive. They only studied 16 females at a sedentary activity. They should also have studied 16 men at the same activity to be able to compare. The reason why we, in some field studies, find that women prefer higher room temperature than men is attributed to the level of clothing. Women adapt better their clothing to summer conditions while men are still wearing suit and tie. So if the thermostat is set to satisfy the men, the women will complain about being too cold. In the standard, this adaption of clothing to summer is taken into account so if the standard is followed the women would be satisfied; but maybe not the men.”
ASHRAE President David Underwood notes that the standard has been continually refined and updated since it was first published in 1966, reflecting changes in the industry and new research as it becomes available. Standard 55 is based on an earlier document developed in 1938 by two predecessor societies of ASHRAE, titled Code for Minimum Requirements for Comfort Air Conditioning.
Whether standards are to blame for over-air-conditioned buildings is unclear. An article in the New York Times found that over-air-conditioning is considered a status symbol by many businesses.
Photo of female office worker via Shutterstock.