Homes and offices use a lot of energy, for example for heating and cooling. The Netherlands wants to replace the use of natural gas in the built environment with sustainable alternatives. Energy saving through renovation of buildings, smart technology and changing the behaviour of residents represent the first step in making the built environment more sustainable. In addition, the supply of heat must be preserved. This can be done by means of electric heat pumps and geothermal energy. Together with construction experts from other areas of TNO, ECN part of TNO develops technology such as heat pumps and innovations for heat and cold storage and heat networks. ECN is also developing part of TNO’s knowledge to make buildings energy-producing, through the smart integration of, for example, solar energy into building components. The building and construction sector is a natural partner here, as are companies that manufacture appliances and components and sell these in the Netherlands and abroad.