Energy efficiency is the most effective way of achieving sustainable development goals. Higher efficiency contributes to reduction of greenhouse gas emissions, higher industrial competitiveness, job creation and higher security in energy supply. Sustainable development is the main goal of the European Union which has set itself a 20% energy savings target by 2020. The Republic of Croatia has set the same goal in 2008 by introducing a Building Energy Rating (BER). By introducing the Building Energy Rating and by setting the highest allowed energy class for a certain type of building, the investors are forced to construct buildings that will contribute to energy efficiency. One of the most important factors for achieving the goal is good thermal insulation of building envelope. This can be accomplished by installation of specially developed advanced materials for thermal insulation. Therefore it is essential to know the types of materials for thermal insulation as well as to be familiar with the technology and proper usage of those materials. Due to the fact that the action plan of energy saving by 20 % is supposed to be conducted by 2020, which is a short term, The Republic of Croatia and The European Union have funded Environmental protection and energy efficiency fund in order to co-finance and encourage the investors to contribute to the plan.