People tend to shower more efficiently if they see real-time data about their energy usage as they scrub.

Verena Tiefenbeck at the Swiss Federal Institute of Technology in Zurich and her colleagues equipped rooms at six hotels with a shower meter. Sixty per cent of the meters displayed real-time information about water and energy consumption, along with an animation of a polar bear on a melting ice floe. The remaining 40% of the meters displayed only the water temperature.

None of the hotel guests knew about the experiment, nor were they responsible for the water bills. Even so, guests whose meters provided instantaneous feedback used 11.4% less energy, on average, than those who did not receive this information, suggesting that such measures can cut the public’﻿s consumption of energy and other resources.