Both in Europe and in Croatia, there is a need to renovate old buildings and houses, and over the last decade, increasing efforts have been made to renovate them and increase their energy efficiency. Old buildings built before 1980 predominate, losing large amounts of energy due to a lack of thermal insulation. Back then, construction technology was at a much lower level than it is today and it is estimated that in Europe as many as 75% of buildings are without or with minimal insulation. So, buildings have become the largest single emitters of CO2 emissions, even ¼ global emissions are from buildings. The energy renovation of these buildings has multiple benefits, from the improvement of various sectors of the economy, to the biggest, and that is the impact on the environment. Croatia is a developing country that, with its accession to the European Union, has begun to implement reconstruction measures.The energy recovery of such a significant emitter can affect various negative effects on the environment such as global warming, environmental pollution, nature destruction and biodiversity. The paper analyzes the concepts of green building, possibilities of energy efficiency and renovation in the Republic of Croatia and energy certificates. The aim of this paper is to present the current state of the housing stock in the country and its perspectives and to analyze the Energy Renewal Programs adopted by the Government of the Republic of Croatia according to the instructions of the European Union.