The chapter delves into the importance of enhancing energy savings within the residential sector of the European Union (EU) as a strategic measure to curb energy consumption and greenhouse gas emissions. It mainly focuses on energy saving potential in the residential space heating domain. The chapter explores the market and behavioral barriers to investing in energy-efficient buildings that prevent the full realization of energy-saving potential. It reviews energy efficiency policies at the EU and national member state levels that potentially address these barriers, and it overviews ex-post studies that evaluate the potential effectiveness of these policies.