Testing the Effect of Defaults on the Thermostat Settings of OECD Employees

Default options have been shown to affect behaviour in a variety of economic choice tasks, includinghealth care and retirement savings. Less research has tested whether defaults affect behaviour in thedomain of energy efficiency. This study uses data from a randomized controlled experiment in whichthe default settings on office thermostats in an OECD office building were manipulated during thewinter heating season, and employees’ chosen thermostat setting observed over a 6 week period.Using difference-in-differences, panel, and censored regression models (to control for maximumallowable thermostat settings), we find that a 1°C decrease in the default caused a reduction in thechosen setting by 0.38°C on average. Sixty-five percent of this effect could be attributed to officeoccupant behaviour (p-value=0.044). The difference-in-differences model shows that small decreasesin the default (1°) led to a greater reduction in chosen settings than large decreases (2°). We also findthat office occupants who are more apt to adjust their thermostats prior to the intervention were lesssusceptible to the default. We find no evidence that offices with multiple occupants displayeddifferent patterns in thermostat choices than single-occupant offices. We conclude that this kind ofintervention can increase building-level energy efficiency, and discuss potential explanations andbroader policy implications of our findings.