For new single-family homes, the heat pump has surpassed the gas boiler since 2017 as the most popular heating technology in Germany. Heat pumps are installed in 45 percent of new buildings to provide hot water and space heating. However, as the examples from other European countries such as Finland, Norway and Sweden show, the proportion of heat pumps could be significantly higher. These units offer ecological, energetic and economic advantages that are attractive for the end user and key for the future energy system. No other heating technology is able to provide 1 kWh of heat using less energy. Thus heat pumps can reduce CO2 emissions significantly.