The vast majority of Europe’s buildings and homes were built during the post-war construction boom. In fact, it is estimated that of the 250 million houses in Europe today, less than 10 % were built in the last 10 years. But these homes aren’t just old, they’re also extremely inefficient. How inefficient? According to some estimates, of the between 85 % and 90 % of buildings that are expected to still be standing in 2050, 75 % are energy-inefficient.