Please turn off the lights: the effectiveness of visual prompts.

Two early studies showed that visual prompts can be effectively used to encourage people to turn off the lights in unoccupied classrooms, but they were methodologically limited. The current study used an ABAB-B design with an 11-week follow-up to investigate whether two different visual prompts (large and small signs) could be employed to increase "lights off" behaviour in 17 unoccupied washrooms. The odds were eight times higher that lights would be turned off in washrooms with signs than washrooms without, and large signs trended toward being more effective than small signs. Signs in washrooms with windows appeared to be the most effective, but this finding merits further research. Behaviour change persisted throughout the follow-up period, but reactance by a single washroom user resulted in some signs being removed. Compared to previous research, the current study used an improved methodology with a larger number of study sites. This study demonstrated that a simple, well-designed sign can effectively encourage energy conservation.