A persuasive GPS-controlled thermostat system

Abstract

Using 10 weeks of data from a couple living in an instrumented home, we report on the potential of context-aware power management for energy saving. We identify an opportunity to save on heating and cooling using a system we propose for just-in-time heating and cooling based on travel distance computation from GPS-enabled mobile phones. Analyzing GPS travel data from eight participants (8-12 weeks each) and heating and cooling characteristics from 4 homes, we report results of running computer simulations estimating potential energy savings of a system that could augment existing manual and programmable thermostats. Although manual and programmable thermostats can save large amounts of energy when used properly, studies have shown that well over 40% of U.S. homes may not use energy-saving setbacks when homes are unoccupied. We estimate that using a GPS-enabled thermostat might lead to savings of as much as 7% for some households that do not regularly use the setback features afforded by manual and setback thermostats, without requiring any change in behavior. For some end users, providing one extra bit of information each day could lead to savings as high as 9%, and additional persuasive strategies could save up to 15%. We then report on the implementation of a prototype system and pilot testing of the user interface. We propose five design guidelines for a just-in-time heating and cooling system.