Energy signature methods are applied over three tertiary buildings in the UK, Sweden and Spain, based on both simulations and experimental data, for pre- and post-retrofit scenarios. Variations in their energy profiles relate to differences in climate severity, usage pattern (continuous/discontinuous) and HVAC scheduling. This study discusses the impact of such particularities for obtaining a steady-state linear regression model of the dependence of heating energy load against climate data. The choices of dataset and time step have important implications for the results obtained.The research leading to these results has been partly developed within the RESSEEPE project, funded by the European Union's Seventh Framework Programme (FP7) under grant agreement no. 609377

External Thermal Insulation Composite Systems (ETICS) are increasingly used for the energy-efficient retrofit of buildings. This paper evaluates the in-situ thermal performance of a prefabricated composite panel made of PIR and concrete, by full scale testing of a prototype installed at the KUBIK test facility. Experimental results from measurement show a reduction in the thermal resistance of the ETICS assembly compared to theoretical design values. A number of phenomena have been identified causing multidimensional heat flow of conductive and convective nature,such as thermal bridges at floor slabs and anchors, and thermal bypass of the insulation causing airflow behind the ETICS.The ETIXc project consortium, composed of Sociedad Financiera y Minera, S.A. FYM- HeidelbergCement Group and Prehorquisa. This research work has been aided by the EEA Grants special funding from the Financial Mechanism of the European Economic Area (2009-2014)