Built environment is responsible for 60% of total energy consumption in European countries and 128 million BOE of primary energy in Belgium. The average energy consumption in the residential buildings of Belgium is 70% higher than the EU average and stands at 348 kWh/m2/year. Energy Performance Building Directive (EPBD) provides guidelines for energy performance analysis of buildings in Belgium. In this study, a holistic approach has been adopted to analyse the building stock of Liege, Belgium. This analysis is based on ‘General Socio-economic survey 2001’ and ‘Housing quality survey 2006 in Walloon region’databases. It considers parameters such as buildings age, built-up area, type of heating system, type of fuel used, adjacency, insulation of roofs and walls and energy consumption etc. for an in depth analysis. This study concludes that about 69% of buildings which are constructed before 1945 needs serious renovation towards the improvement of roof and external wall insulation level. It then successfully identifies specific areas which need detailed study to evaluate the comfort status in the existing building stock, improvement of insulation level and its effect on heating energy consumption as well as the economic analysis on energy efficiency measurements.