This paper presents the mathematical procedure for the determination of overall sustainability index of nine options for the agglomeration of economic, environmental and social indicators. Eleven sub-indicators were selected and calculated for all chosen options. In accordance to final energy consumption (for space heating, hot water production, cooking and the household electrical appliances) the selection, defining and determining the economic, social and environmental indicators was developed. It was done for all chosen options selected by qualitative characterization of residential objects in accordance with construction period, type of heating system and type of object (buildings or family houses). Investigation of the influence of non-linear normalization on the sub-indicators' agglomeration was the aim of this paper. Normalized sub-indicators are obtained by selection of the appropriate linear (theta = 1) or non-linear function (theta not equal 1). Sustainability index and its standard deviation were calculated for different value of the parameter theta and each option in six different cases. The functional dependence between the sustainability index and the associated standard deviation of the theta parameter (characterizing the way of normalization) was obtained. (C) 2012 Elsevier B.V. All rights reserved.