Grey box models are a solution for evaluating and quantifying the effect on building thermal performance of different energy saving measures. They are usually used to predict a building thermal performance, and applied to energy systems. This paper presents the application of a grey box model to evaluate the thermal performance of a reference social housing building, focusing on its potential to evaluate the thermal performance of building passive elements (building envelope). A methodology to be used by public administration (to evaluate the effectiveness of a given energy renovation work) is also proposed. Firstly, a monitoring carried out in an empty social housing dwelling during 3 months is presented. Afterwards, a grey box model development is carried out using obtained monitoring data. Model development as well as some general model results are presented and evaluated. Finally, a methodology proposal to be applied by public administration is presented. By monitoring and developing a grey box model of a social housing building, this research aims to explore the possibilities of grey box models as a tool to represent in an accurate way the thermal performance of a dwelling, focusing on evaluating building passive elements and their effects on building energy consumption. (c) 2015 Elsevier B.V. All rights reserved.