The Power Management User Interface Study

Research shows that many desktop computers are left on for long periods when not being used. Getting computers to transition to sleep mode during these periods would save a substantial amount of energy. The research team developed and tested a new software application that manages computer sleep settings, called Power Management User Interface. The goal was to create a user interface that encourages desktop computer users to use the automatic sleep settings already available on computers more efficiently. The design of the user interface was based upon past research on the efficacy of various energy feedback programs to encourage pro-environmental behaviors more generally, and on behavioral theories. A field test of 407 office desktop computers was conducted to test the effectiveness of this software application and to collect data on users’ behaviors toward power management. At baseline, only 13 percent of computers had computer sleep settings enabled, but more than 56 percent of subjects reported the settings were enabled. Findings suggest user confusion about settings that is correlated to lack of use and knowledge. Subjects exposed to the Power Management User Interface application were significantly more likely than control subjects to enable their computer sleep settings and to reduce the delay time. Treatment subjects' computers subsequently spent less time idle and more time in sleep mode than control subjects' computers. However, more than half of computers with sleep enabled experienced at least one problem with sleep transitions being blocked, and 27 percent exhibited substantially higher idle time and lower sleep time than expected. These sleep blockers reduced the effects of enabling sleep settings and thus the effects of the Power Management User Interface treatment. However, treatment subjects still saved an average of 23.7 percent more energy than control subjects. These results provide strong evidence for the effectiveness of changing computer users' energy-saving behavior using feedback and encouragement. They also illustrate the importance of solving technical problems that inhibit sleep transitions. California taxpayers will benefit from this software because it will reduce energy use by desktop computers.