The building sector, accounting for about 40% of the energy consumption of the EU, provides a great potential for cost-effective energy savings. The recent recast of the Directive in 2010 calls for more concrete actions and further harmonisation of the approaches in the Member States to realise the full potential for energy savings in buildings. It contains a new article about the need to increase the number of buildings which go beyond current national requirements, and to draw up national plans for increasing the number of nearly zero-energy buildings (NZEB) with the final target that by 2020 all new buildings shall be nearly-zero energy. Nearly zero-energy buildings are buildings with a very high energy performance, where the remaining low energy demand can be supplied to a significant extent by renewable energy. However, no agreed definition of nearly zero-energy buildings is available yet. In this paper, the proposed requirement system for nearly zero-energy buildings in Hungary is presented. The effect of the new requirements on the building envelope and the building service system is analysed. A fundamentally new approach in building design will be necessary treating functional, constructional, aesthetical and energetic aspects on the same level. Measures for reducing the energy demand are analysed and the reduction in energy use is calculated. Instead of choosing a few typical buildings, the energy demand analysis is done on a large building sample of detached houses. The building sample is described by a combination of geometric parameters, the realistic ranges of which were determined based on statistics, functional and architectural considerations. The ‘global costs’ or life cycle costs of the design options are evaluated taking into account the investment costs, the costs of maintenance/replacement and the energy costs as well.
