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Gender and Thermal Comfort

Feb. 11, 2015
Most of the women I know—my wife included—generally are more likely than men to report feeling cold in an air-conditioned space. Well, it turns out they have science on their side.
Most of the women I know—my wife included—generally are more likely than men to report feeling cold in an air-conditioned space. For me, the telltale sign when I am doing an energy audit in a commercial office building is sweaters on the backs of chairs—even (or, maybe as we’ll see, especially) in July in South Florida!

In September 2013, I posted “Balancing Energy Conservation and Occupant Comfort,” in which I poked some fun (good-naturedly, of course) at my wife for almost always feeling cold when in an air-conditioned space. Well, it turns out she and her friends have science on their side.

Recently, I learned of a report—“Thermal Comfort and Gender: a Literature Review,” published in the April 2012 issue of Indoor Air—in which the author, Sami Karjalainen, examines various scientific studies detailing the effects of gender on indoor thermal comfort. In more than half of the studies that were analyzed, from both laboratory and field environments, women were more dissatisfied than their male counterparts when experiencing the same indoor-temperature and relative-humidity (RH) conditions. The analysis also found women were more sensitive than men to changes in those conditions, especially to cooler temperatures.

There are both physical and physiological factors that can affect our thermal comfort and explain why women may tend to feel colder than men when exposed to the same conditions. A May 1998 research letter in The Lancet (the British medical journal) confirmed the old adage “cold hands, warm heart” probably was based on the fact women have slightly higher core temperatures than men (97.8°F vs. 97.4°F), but their hands are colder by almost 3°F. Other physiological factors that may influence a person’s response to temperature include body type (amount of fat and muscle mass) and size (stature). Smaller, thinner folks will lose heat faster than larger, heavier types, and using muscles generates heat. Physical factors, such as proximity to cool air registers, drafts, and clothing, obviously, will affect thermal comfort for both men and women. However, if the men are wearing dress shirts with ties and blazers or suit jackets, and the women are wearing skirts and blouses—with their necks and ankles exposed—the women will and should feel colder!

There also is the effect of indoor RH on thermal comfort. We know (and if we don’t, ASHRAE tells us) that 74°F at 40-percent RH feels cooler than 74°F at 65-percent RH. We’ve also found, in numerous studies over the years, that many or most buildings were—until recently—designed with oversized air-conditioning systems. The lesson here is for designers to right-size HVAC systems. And because we cannot design different systems based on gender, maybe managers should be more sensitive to and flexible in personnel placement. Obviously, everyone cannot have a corner office with a view of the water, but if a very petite woman is particularly sensitive to the air conditioning, she probably shouldn’t be sitting under a wide-open ceiling diffuser.