In the yearly United Nations Climate Change Conferences the participating countries have agreed to establish legally binding obligations to reduce greenhouse gas emissions. The climate change reduction measures as set out in the Paris Agreement are translated for the various countries into specific regulatory requirements by the nationally determined contributions – NDCs. The necessary reductions in greenhouse gas emissions until the year 2050 are split up for the various sectors like buildings, energy, industry, transport, agriculture or waste management. The building sector is decisive to limit global warming stemming from the increase in CO2 emissions. If the maximum temperature rise due to CO2 emission should be really kept to 2.0% (or even 1.5%) how much does the building stock has to decarbonize by when? Is this achievable for Europe? Seventy-five per cent of buildings in Europe are energy inefficient. Most of today’s buildings will still be in use in 2050. The annual renovation rate is only around 1.2 per cent. Investments in higher energy efficiency in real estate are often seen as low return and high risk. The perception of high risk is related to unclear investment costs, uncertain financing options and payback periods that are considered long. It is examined how the required route to net-zero for the real estate sector according to the nationally determined contributions match the present circumstances of the existing building stock in Europe.