Energy Efficiency in Building as a Basic Prerequisite for a Long Term Energy Strategies Realization, Environmental Protection and Sustainability

Energy efficiency in buildings at the low-energy and 'passive house' standard levels is presently the basic prerequisite for considering and formulating long term strategies, which with the task of meeting energy needs and system maintenance respond to requests of environmental protection and improvements in the context of sustainable development. Orientation to sustainable development is integrated in the development strategies of Croatia. The application of renewable energy sources, in particular solar energy in passive and active systems in the architecture is permanently confirmed by conducting energy monitoring and growing number of domestic studies, projects and realizations. The long-time research project of the European Union Cost Efficient Passive Houses as European Standards (CEPHEUS) with scientific monitoring corroborated energy and economic efficiency of such architectural designs in Germany, France, Austria, and Switzerland. Thus, the 'passive house' is proposed as a standard of residential architecture, but also of the construction of other functional types of architecture in general. The accomplished energy efficiency and verified favorable profitability of investment developed new forms of incentives to low-energy and passive architecture and relevant changes in concepts of long term energy strategies in the European Union member states. In Austria the 1000th passive house was built, and the city of Frankfurt/M brought decision regarding financing building construction through the city budget at the 'passive house' level. The new Technical Regulation on energy savings and thermal protection in Croatia, which is effectively in force as of 1 July, is a long-awaited step towards energy efficiency. Although, according to this Regulation the tolerance in energy use for space heating goes, in worst case calculation, up to 89 kWh/m2 a year, any other more favorable calculation with obligation to calculate the share of solar radiation for buildings, opens the way for understanding of investors and users, and probably to necessary forms of credit financing and subsidizing as known in the EU. The question now arises of lacking calculation of solar radiation for family houses. Energy efficiency of built structures of low-energy standards and early-built 'passive houses' in Croatia point at full justification of continued construction and development of such energy concepts in relation to domestic experience and their place in the construction industry and energy sector perspectives until 2050. In this paper the said assumptions are illustrated and interpreted through examples of projects and realization of family houses in Croatia, multi-apartment houses in Darmstadt and first school building built based on the 'passive house' standards in Frankfurt. Wind energy and hydrogen in accordance with global growth of renewable market and their share in energy increasingly influence the investments in the construction sector. Energy efficiency based on renewable energy sources in the construction industry as well as in other energy sectors is increasingly important factor of developing energy security, economic development, environmental protection and sustainability.(author)