July 24 (Bloomberg) -- Takashi Kadokura used to strip down to his underwear when working late because of the heat.

“We couldn’t concentrate on our work,” said Kadokura, 37, then an economist for Dai-ichi Life Research Institute in Tokyo. “The air conditioning was set at 28 degrees (82 degrees Fahrenheit) and we weren’t allowed to change it.”

The experience led Kadokura to question the Japanese government’s “Cool Biz” policy, which recommends companies set air conditioners at 28 degrees to reduce carbon emissions. Kadokura says sweaty offices lead to lower productivity, and estimates the policy reduced economic growth in 2008 by 653 billion yen ($6.9 billion) or 0.13 percent of Japan’s gross domestic product of 497.4 trillion yen.

Cool Biz was created as part of the government’s pledge to cut greenhouse gases emissions by 6 percent in the 22 years starting in 1990 as part of the Kyoto protocol. Toyota Motor Corp., Panasonic Corp. and Japan’s largest banks are among about 30,000 organizations that have signed on to the principles of Cool Biz, according to the Ministry of Environment’s Web site. The program is voluntary and no penalties are assessed if the guidelines are not followed.

Kadokura, who now runs the Yokohama-based consultancy BRICs Research Institute, says his estimates are based on research by Shinichi Tanabe, a professor of Architecture and Environmental Engineering at Tokyo’s Waseda University. Each degree the temperature is raised above 25 degrees cuts worker productivity by 1.9 percent, said Tanabe.

“The temperature can easily rise above 28 degrees in areas influenced by heat from office equipment,” Tanabe said in a telephone interview. “The concept of Cool Biz is great but we need a more scientific approach to decide the temperature.”

Better Off Naked

Cool Biz got its name in 2005 when former Prime Minister Junichiro Koizumi called on his countrymen to dump ties and jackets and dress down in the summer months from June to September to keep cool.

Koizumi set the tone by showing up for work wearing open- neck Okinawan shirts. Lighter clothing isn’t much help to office workers toiling in 28 degrees, says Kozo Hirata, who studies clothing physiology at Kobe Women’s University.

“If you put on clothing and work actively in an office at that temperature, you will probably begin to sweat,” Hirata said in an interview. “Sweating is the last resort to cool down a heated human body. The target is too high.”

To feel comfortable working in temperatures in the upper 20s, people “would have to go naked,” he said. “Wearing shorts and T-shirts might make it bearable, but that hardly fits with Japanese office culture.”

Hotter Summers

The United Nations last August started its “Cool UN” energy-saving campaign at its New York headquarters, choosing a temperature target of 25 degrees. That’s lower than the Cool Biz target, even though Tokyo and other Japanese cities have hotter summers than New York.

The average high temperature in Tokyo in August is 31 degrees Celsius, or about four degrees higher than New York’s 27 C, according to The Weather Channel’s Web site. Tokyo’s average relative humidity in the month is a tropical 74 percent.

In Nagoya, central Japan, an office worker at a construction consulting firm said his company requires suits in the office yet keeps the thermostat at 28 degrees.

“It’s extremely uncomfortable,” said the worker, who would only give his family name, Nakano. “Everyone at my office complains about the situation, but they don’t do anything.”

Sanyo Electric Co., the world’s largest maker of rechargeable batteries, has extended its Cool Biz campaign through October at its headquarters in Osaka, while acknowledging it doesn’t always make sense.

“Sometimes it gets too hot,” Sanyo spokesman Masatsugu Uemura said. “So the temperature may need to be set below 28 degrees in some offices.”

Sapping Growth

Kadokura said if Japan wants its economy to grow at a time when its population is declining, it needs to boost productivity. A lower birthrate means the population, about 128 million in 2005, could shrink 26 percent by 2050, according to the National Institute of Population and Social Security Research in Tokyo.

Japan’s economy is projected to shrink 6 percent this year, the second-biggest decline after Germany among Group of Seven nations, according to the International Monetary Fund.

“We are behind our goal in cutting emissions, but after Cool Biz, Japanese have become more aware of energy-saving measures,” said Toru Sugiyama, a spokesman for the Environment Ministry. “I don’t think we need to change what we are doing.”

Sugiyama said the ministry has never received a complaint from a worker about the heat.

“We aren’t forcing companies to raise or lower the temperature,” he said. “We expect each employer can adjust to the environment in summer by setting up electric fans, changing the office layout or giving workers handheld fans.”

Kadokura disagrees.

“The small reduction in greenhouse gases doesn’t justify the effect that uncomfortably hot office temperatures have on workers,” he said. “We should focus on raising productivity to boost growth and Cool Biz seems to go against that.”

To contact the reporter on this story: Masatsugu Horie in Osaka at mhorie3@bloomberg.net

Last Updated: July 23, 2009 19:17 EDT