Is it reasonable to invest - thoughts and money - in the energy refurbishment of historic buildings? This paper quantifies the potential impact in terms of climate protection and enhanced living conditions – looking not only at exemplary listed buildings, but more generally historic “cityscapes”. Statistics reveal that 14% of EU-27 building-stock dates before 1919, other 12% between 1919 and 1945 (with considerable national differences), corresponding to 30 resp. 55 million dwellings and 120 million Europeans living there. With information on climatic regions and building performance a heating-demand of 855 TWh corresponding to more than 240 Mt CO2 can be estimated. Refurbishment can save 180 Mt CO2 within 2050 (3.6 % of 1990’s EU-27-emissions), while bringing indoor comfort increases (higher surrounding temperatures, less draughts, ...) and energy-costs decrease. Finding conservation-compatible solutions enhances therefore long-term-conservation and sustainable management of our towns.