Building energy consumption following energy certificate vis a vis of real energy consumption data

Abstract

The purpose of the Energy Performance of Buildings directive implementation in EU was to reduce the energy consumption in building sector and make it more efficient. The calculated energy consumption was chosen as an indicator of energy performance certification for implementation of the Energy Performance of Buildings directive in Lithuania. The calculated energy consumption and real energy consumption of few buildings was compared. The calculated energy consumption was evaluated by the Lithuanian norm STR 2.01.09:2005 „Building Energy performance. Certificate of energy performance“. The real energy consumption was recalculated to normal year. The average of two years of the real energy consumption was taken into account for comparison. Old administrative and residential buildings were analyzed. All objects were partially renovated. The difference of results and the reasons for it are presented in the article. The building energy consumption following energy certificate is only theoretical value, which depends on building envelope, but not on engineering systems. The main reasons of different results are: insufficient evaluation of engineering systems and ineffective building energy management systems.