The great east Japan earthquake of March 11, 2011, wreaked enormous damage, forcing the Japanese government to mandate a 15% peak power reduction to address shortages in summer. Office workers were forced to be patient. The present paper reports the results of field studies conducted in Tokyo office buildings during summer to understand the relationship between indoor environment, productivity, and energy conservation measures under the mandated limits. Occupants generally expressed discomfort regarding the high temperature, but widely accepted the decrease in illumination from 750 to 300-500 lux. Increased awareness regarding power savings was found, with more than 90% of people accepting the poor indoor environment in light of the shortages that year. Clothing and raising set point temperature recommendations made by the Super Cool Biz campaign were followed in most offices. However, self-estimated productivity was 6.6% lower than last summer. Strategies for electricity savings that do not affect productivity are necessary.