There’s an elephant in the tatami room – Japan has absolutely zero mandatory building energy efficiency standards. This nation’s buildings consume about 40% of all primary energy, and about 70% of all electric power. Simply improving building efficiency would dramatically change the electric power demand side of the equation in this nuclear catastrophe challenged nation, and yet there is no building code regarding efficient energy usage.
Japan is no stranger to strict building standards, it has some of the worlds toughest quake resistance and fire proofing building code. For some reason the government has never found it necessary to create efficiency requirements by law.