The Heat is On

Summer is almost upon Japan.  Down in Okinawa, some places have already felt 30*C heat that humidity makes even worse.  So how does Japan cope with the heat, especially given the likelihood of power shortages due to the limitation of nuclear power since 3/11?

Constructing for Cool

Much of Japanese architecture still reflects the traditional Japanese method of staying cool.  Raised floors, large windows, sliding doors, and the over-all draftiness of many Japanese houses contribute to their ability to stay cool in summer, if not warm in winter.

Traditional houses were often built with sections that could be removed.  Often, whole walls can be pulled away to open living areas to catch breezes.   In more modern housing, there are often still large windows and glass doors that can be opened to let in the breeze, while screen keep out the bugs.

Since even most apartment style buildings have raised floors, there is often a way for air to circulate under the floor, keeping them from over-heating as well.  Modern buildings have also begun utilizing solar panels to turn the strong summer sun into extra energy and to turn heat energy into something more useful.


It is fortunate that many summer food items grow on vines.  Goya, hechima, cucumber, and even watermelon all grow on vines and often have large leaves.  In Japan, it’s no surprise that these have become favorite summer foods.  Those large windows I mentioned earlier can become a significant problem if they face the sun, especially if they let in more heat than wind.  One alternative is a green curtain.  A net can be hung in front of any area you would want to shade, then the plants can be put in (either pots for second story, or in the ground if you are lucky enough to have a garden).  The result is a significant decrease in temperature inside the house, while still being able to catch a breeze.  Plus you will have fresh vegetables to eat and share.

Super Cool Biz

Traditional Japanese dress was always rather airy.  The toga-like kimono and other wrap-able wear meant their clothing would not keep in the humid heat.  Of course, that kind of dress is rare today, with society having strong expectations about acceptable dress codes for various jobs.

Rather than go unprotected, most Japanese people choose to wear long sleeves and pants, even in the heat.  This is mainly from a concern over skin cancer.  You’ll often see older women completely covered from head to toe, with large hats and scarves over their eyes.  Not everyone is so careful, but many of the materials worn during the summer months are far more open to airflow than cotton, making them more livable.

Still those strong societal expectations for dress code are a much bigger problem when the air conditioner is off to preserve power.  There isn’t much large buildings can to do decrease the temperature.  Most that can already use tinting or green curtains if they are viable.  Last year, after 3/11 the Japanese government promoted ‘Cool Biz’ to help take the burden of power conservation off the working class citizens and government employees.  Essentially the demanded level of formality in dress (ie how many layers) was dropped a notch.  This let suit wearers get away with short-sleeved dress shirts, or polo shirts instead.

This year, the news, government, and many companies are promoting ‘super cool biz.’  This means mainly the same as last year.  In Japan, its often common to repackage the same thing with a new name, simply as a marketing ploy.  That’s not to say there won’t be some super cool biz people out there with super cool clothes (I did see short pants as the lowest level acceptable.  Shorts are still out).

Of course, down here in Okinawa, cool biz has been the name of the game for ages.  In a place where humidity and heat are a fact of life, Kariyushi wear is the official formal wear in most cases having the same level as a suit.  Kariyushi is similar to a Hawaiian shirt, but of better quality and worn formally with slacks and dress shoes.  Today there are many kinds of Kariyushi, and they certainly beat out a suit.

Checkout UniGlo’s before and after slide show for a better idea (jp).