i4energy: Measuring the Usability of Thermostats and Other Really Annoying Devices
January 21, 2011
Residential thermostats control over 10% of the total energy use in the United States; however, the details of how people use them have been largely ignored. Five investigations of usability of programmable thermostats were undertaken. The majority of occupants operated thermostats manually, rather than relying on their programmable features, and almost 90% reported that they rarely or never adjusted the thermostat to set a weekend or weekday program. Photographs of thermostats were collected through Amazon Mechanical Turk, which revealed that about 15% of the thermostats displayed the wrong time and that about 33% of the respondents set their programmable thermostats on "long term hold". We developed and tested a measurement protocol that could quantitatively distinguish usability among five thermostats. This protocol will be used to establish minimum levels of usability in programmable thermostats and other energy-using devices with complex controls.