The business case for energy efficiency is a powerful one. At the end of 2010, the Carbon Trust reported that the average return on investment of energy-efficiency projects carried out in commercial premises is 48%. Increasingly, it is becoming clear that to invest in sustainability is to save money. But while the UK government is supporting carbon reduction by introducing grants and green initiatives, these have done little more than skew people’s perception of what represents an energy saving. With heavy focus applied to insulation and heating, cooling strategies have been left rather more out in the cold. The hot…