Environmental protection, high energy consumption, greenhouse gas pollution and the importance of using renewable energy are becoming more and more popular topics today. With joining European Union, the Republic of Croatia has started to take more and more steps towards sustainable and energy-efficient economic development. This is economically important topic and Croatia, noting the importance of energy efficiency in environmental protection, places it at the very top of its strategic goals. Energy efficiency and sustainability are under increasing attention in the building industry due to the very clear fact that the construction sector is the world's largest energy consumer. Because of this reason this thesis focuses on the various energy renovation programs for public sector buildings, commercial buildings, single-family homes and multi-family dwellings, which aim to inform the public about the overall energy renewal process in order to stimulate and increase renewal activity itself, reduce energy consumption and harmful effects on the environment, increase use of renewable energy sources, achieve energy savings and increase economic growth and development. In the thesis are clearly identified some of the basic factors and preconditions that contribute to better quality project implementation and the currently available sources of energy renewal financing for the public sector, legal and natural persons. Given the very high costs, good lending conditions at commercial banks for legal and natural persons, basic budgetary preconditions for acquiring the right to finance within state institutions, opportunities to obtain the right to partial financing provided by numerous national and European institutions promote long-term sustainable development in the area energy.