Office building managers who set air conditioners to frigid temperatures are not only sending shivers up the spines of workers, they're also wasting money and energy, a new study finds.
Air-conditioning and heating standards in office environments were originally set based on the resting metabolic rates — a measure of how much energy a person uses at rest — for males, the researchers said. In fact, the standards were developed in the 1960s to accommodate the resting metabolic rate of a 40-year-old man who weighs 154 lbs. (70 kilograms), they said. As such, this tends to make temperatures uncomfortable for people with varying body types, particularly female workers.
By adjusting thermostats, building managers can help make employees more comfortable at work while simultaneously saving money from lower heating and cooling costs, said the study's lead researcher, Boris Kingma, a biophysicist at Maastricht University in the Netherlands. [Top 10 Craziest Environmental Ideas]
Kingma and his colleagues examined the physiology of 16 lightly clothed women who performed light office work in a climate chamber. Instruments in the chamber calculated their metabolic rates by measuring the women's oxygen consumption and carbon dioxide production. The researchers also measured the women's skin temperature and the air temperature and humidity of the chamber.
The women's metabolic rates were significantly lower than the standard values based on the 40-year-old man, the researchers found. One reason is that women are generally smaller than men and have a higher percentage of fat cells than their male counterparts, Kingma said. Fat cells produce less heat than muscle cells, which partially explains why women tend to have lower metabolic rates compared with men, he said.
The new findings also support previous research from other studies, which show that women prefer temperatures that are about 5.4 degrees Fahrenheit (3 degrees Celsius) higher than men do, Kingma said.
"The current metabolic standards should be adjusted by including the actual [metabolic] values for females to reduce gender-discriminating bias in thermal comfort predictions," the researchers wrote in the study.
New heating and cooling standards should take into account the average age, sex and body size of workers, although more research is needed to determine the best formula, the researchers said.
Climate-control settings in buildings are built to help people maintain their core body heat, which is typically about 98 degrees Fahrenheit (37 degrees Celsius), Kingma said. If a person enters a room that is too hot or too cold, the body will use energy, such as by shivering or sweating, to keep the body at the right temperature, he said.
What's more, office workers tend to make more mistakes when they're stationed in chilly office environments than they do in warm ones, a 2004 Cornell University study found. The month-long study showed that when ambient office temperature increased from 68 degrees to 77 degrees Fahrenheit (38 degrees to 43 degrees Celsius), typing errors fell by 44 percent and typing productivity increased by 150 percent.
However, sometimes it can be good for the body to use a little energy during the day. Many office workers spend the majority of their days sitting at desks, and it might be beneficial if their bodies burn a few calories to keep warm or stay cool, Kingma said. But temperatures in a shared space (such as an office) shouldn't be too cold or too hot that people feel uncomfortable, he said.
The researchers encourage engineers, architects and building managers to be aware of, and possibly implement, an improved heating and cooling standard once it's available.
"I have spoken with a few professionals in the field, and their reactions are very positive," Kingma told Live Science.
The study was published online today (Aug. 3) in the journal Nature Climate Change.
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