Controlled trials are now beginning to be used to test interventions designed to increase energy efficiency. In a trial in Norway [2] the labelling of appliances was changed to make it more meaningful to consumers. Labels in some stores showed lifetime electricity running costs and improved staff training while the control groups had labelling showing only annual kWh and no training. For fridge-freezers no significant effect was found. For tumble dryers the combined label and training reduced average energy use of tumble dryers sold by 4.9% while training alone led to a 3.4% reduction. The effect was strongest initially, but declined over time.