Energy efficiency in the built environment can make significant contributions to a sustainable energy economy. In order to achieve this, greater public awareness of the importance of energy efficiency is required. In the short term, new efficient domestic appliances, building technologies, legislation quantifying building plant performance, and improved building regulations to include installed plant will be required. Continuing these improvements in the longer term is likely to see the adoption of small-scale renewable technologies embedded in the building fabric. Internet-based energy services could deliver low-cost building energy management and control to the mass market enabling plant to be operated and maintained at optimum performance levels and energy savings quantified. There are many technology options for improved energy performance of the building fabric and energy systems and it is not yet clear which will prove to be the most economic. Therefore, flexibility is needed in legislation and energy-efficiency initiatives. (c) 2008 Queen's Printer and Controller of HMSO. Published by Elsevier Ltd. All rights reserved.