The building sector accounts for up to one-third of the EU total final energy consumption, as most European houses and offices were built before 1990 and they did not undergo any major renovation. They show poor thermal insulation capability, and few strategies are implemented today to control and reduce the electricity and heating demands. Almost 40% of the total CO2 emissions in Europe comes indeed from the building sector, both indirectly during the construction process and directly in the operational lifetime. The set of contaminants, however, also includes hydrofluorocarbons (i.e., greenhouse gases), fine particles (PM2.5/PM10) and toxic dusts, depending on the energy mix of each country.