In practice a number of calculation tools are used to calculate annual energy flows in buildings. Their use yields accurate results but requires the input of a large number of parameters in the complex calculation procedures involved. The values of these parameters are usually known only after the planning process of a building has been completed. A simplified evaluation method for energy efficiency in single-family houses has been developed with the aim of using as few building parameters as possible with the simplest calculation procedures possible. The calculation model was created on the basis of results obtained in a research study conducted on a large statistical sample of Slovenian single-family houses. The correlation analysis carried out showed that the heat balance energy flow values calculated are closely related to certain building quality parameters. The energy balance complexity makes normal quantity parameters less related to energy flows, and they cannot be used in simplified evaluation models. The new evaluation method can be used in two modes by applying different quality parameters, depending on their availability. If more complex input parameters are used, the results of the method are more accurate, and so it can also be used for a preliminary assessment of individual projects. (C) 2013 Elsevier B.V. All rights reserved.