According to the recast of the Energy Performance Building Directive, Member States must give an exact definition for nearly zero-energy buildings to be introduced from 2018/2020. The requirement system stipulating the sustainable development of the building sector is usually based on the analysis of a few reference buildings, combining energy efficiency measures and HVAC systems. The risk of this method is that depending on the assumptions either the requirements do not provide sufficient incentives for energy saving measures and renewables or the requirements cannot be fulfilled with rational solutions in many cases. Our method is based on the artificial generation of a large building sample, where the buildings are defined by geometric and other parameters. Due to the large number of combinations, the effect of many variables appear in the results, with the deviations reflecting the sensitivity of the energy balance. The requirements are set based on some fundamental considerations and the statistical analysis of the sample. The method is demonstrated on the example of setting the requirements for residential buildings in Hungary. The proposed requirements are validated against the common European targets. The suggested method is suitable for developing building energy regulation threshold values, certification schemes or benchmarking values. (C) 2014 Elsevier Ltd. All rights reserved.