The main aim of the European Union is to protect and preserve the environment, and the EU initiative is to reduce greenhouse gas emissions. Consequently, the City of Zagreb was among the first European cities that signed Covenant of Mayors and has developed an Energy Sustainable Development Action Plan, that defines energy efficiency measures for construction, traffic and public lighting, and is being implemented by 2020. The purpose of this research is to stimulate the importance of energy efficiency by presenting all important facts, essential for easier application of energy efficiency, in other words the purpose is promotion of energy efficiency and renewable energy sources. The work is based on two hypotheses: 1. Investment projects in the above sectors of the economy reduce the share of gray economy in the construction sector, 2. Such projects increase the recruitment of qualified workforce. The research was conducted on the basis of the energy efficiency measures set out in the Energy Sustainable Development Action Plan of the City of Zagreb, which predicts a reduction of CO2 emissions by more than 20% by 2020. and it is related to the general consumption sector. The Action Plan defines eleven energy efficiency measures in the general consumption sector. Regarding the financing of energy efficiency, it is important to emphasize that Croatia already has an Environmental Protection and Energy Efficiency Fund, which will continue to be the most important financial support for the implementation of the Energy Efficiency Policy. Through its funds, the EU offers substantial financial resources in the next budget period, especially for the area of energy efficiency and renewable energy sources. However, other forms of funding should be established. In accordance with the recommendations of the European Union, the tax system should be used to stimulate energy efficiency. Currently this is not the case and it is recommended to revise the tax system to determine the appropriate ways of using it in terms of energy efficiency.