The Institute of Directors headquarters in Pall Mall needed to replace their gas boilers and meet emissions targets in terms of CO₂ and NOX. With a large daily occupancy, large professional kitchens, cold stores, dining rooms, meeting rooms and conference rooms, there is a constant and large demand for hot and cold water. The IoD HQ is a listed building, with most of the plant in the basement feeding ageing pipework distribution systems. Power Plan Services evaluated the legionella risk, introducing a fully L8 compliant system. New water tanks ensured potable quality water across the whole site. Monitoring of water consumption identified quick wins to save 20,000 litres of cold and 2,000 litres of hot water per day. Finally new designs using high efficiency gas-fired condensing boilers produced significant energy savings.