The IEA Technology Roadmap Energy-Efficient Buildings: Heating and Cooling Equipment shows how technologies such as solar thermal, heat pumps, thermal energy storage and combined heat and power for buildings have the potential to reduce carbon dioxide emissions by up to 2 gigatonnes (Gt) by 2050--around one-quarter of today"s emissions from buildings--and save 710 million tonnes oil equivalent (Mtoe) of energy by 2050.