Croatian Solar House (CSH) is basically an energy-ecological project with the main goal reduction of energy consumption, its production by renewable energy sources, having as a consequence benefical lowering in CO2 emission. It follows the “ Green paper” of European Commission 2000, and its concept is in full accordance with current European trends, described in the program called “ Intelligent Energy for Europe” . As 32% of total final consumption in Croatia corresponds to households, they will be in focus of our interest. In this sense, we shall apply new approaches for energy efficiency in households (like in the European program SAVE) which can save substantially energy in our country. Additionally, in CSH we will also use new technologies for energy production, using renewable energy sources (as in the European program ALTENER), namely photovoltaic and renewable energy sources (based on our own patents) as well as hydrogen fuel cells (from electrolytic and/or reformed hydrogen). As a construction facility, CSH is defined as a passive solar house whose architecture and constructional technologies (insulation, greenhouses, special windows and doors as well as other building elements) provide almost complete energy needs for heating from surroundings, aup to the maximal thermal consumption of 15 kWh/(m2yr). The rest of the thermal energy requirements will be covered by combined systems of energy reception, storage and distribution (solar thermal collectors, heat pumps and recuperators, ventilation etc). On the other hand, saving in electrical energy will be achieved by using the most efficient electrical appliances and lighting. The basic model of CSH will be upgraded by new technologies until it becomes energy rational house, i.e. “ Intelligent energy independent house” . After construction, CSH will be a multifunctional building: (i) a demonstration facility of the above mentioned technologies, (ii) a laboratory for measurement of energy flow and other process variables inside the house, with studies of possible improvements in new technologies, (iii) a national centre for certification of solar-hydrogen devices, which will be incorporated in the network of the corresponding centres in Europe. In order to comprise all these functions, the Centre for solar-technological research in the CSH will founded, closely collaborating with institutions in this field, as well as with industry.