CO2 emissions from the building sector have been the highest ever recorded in 2019, and the push to decarbonize the sector has been losing momentum since 2016. However, investments in energy efficiency technologies such as thermal energy storage, electrochromic smart windows and Whole Building Energy Modelling have been growing, and on the political level, initiatives such as the European Green Deal are pushing for a circular value chain to be integrated into the construction sector. Green technologies are available in many areas.