IEA-ECBCS Annex 53

Untitled document

Total Energy Use in Buildings: Analysis & Evaluation Methods

Contacts : S.Bertagnolio, R.Ruiz, Ph.André, V.Lemort


One of the most significant barriers for achieving the goal of substantially improving energy efficiency of buildings is the lack of knowledge about the factors determining the energy use. Also policies agreements about energy saving targets (e.g., Energy Performance of Buildings Directive of the EU) as well  as agreements about limiting greenhouse gas emissions are based on a knowledge of building energy consumption, in which a complex array of factors, including  the user/occupant behavior, play a significant role. There is often a significant discrepancy between the designed and the real total energy use in buildings. The reasons for this discrepancy are generally poorly understood, and often have more to do with the role of human behavior than the building design.

This discrepancy leads to misunderstanding and miscommunication between the parties involved in the topic of energy savings in buildings:

  • Despite the fact that the building regulations have been strengthened in many countries with respect to energy savings, the real energy consumption is not decreasing at the same rate and on many occasions even is increasing. Buildings and their systems improve, but building usage and activities in buildings can lead to an increasing energy consumption
  • The implementation of energy saving measures is supported and enforced via standards and regulations. These standards and regulations address human behavior and activities in buildings for the average situation and conditions and exclude non-building related issues. Instruments based on these standards, such as Energy Performance Rating (EPR) and labeling systems more and more lose the credibility of the public as they do not reflect the real energy consumption of a building.
  • For investors (property developers, banks, insurance companies, public and private services corporations) in the field of energy, instruments are lacking that enable the assessment of the energy use of buildings and give information about real cost-benefit relationship between investments in energy saving measures and profits.

In fact, building energy consumption is mainly influenced by six factors: (1) climate, (2) building envelope, (3) building services and energy systems, (4) building operation and maintenance, (5) occupants’ activities and behavior and (6) indoor environmental quality provided. The latter 3 factors, related to human behavior, can have an influence as great as or greater than the former 3 ones. The user related aspects and behavior effects can be seen from the large spread in energy use for similar or identical buildings, but a distinction between the building related and the user related energy part cannot established. All six factors need to be investigated together to understand building energy consumption data. Detailed comparative analysis on building energy data, concerning the six factors mentioned above, would provide essential guidance in identifying energy saving potentials and opportunities.

6 mains influence factors


The ultimate outcome of this project is strengthening the robust prediction of energy usage in buildings, thus enabling the proper assessment of short- and long-term energy measures, policies, technologies. The main objectives are to:

  • develop a new methodology for analysis of building energy use that makes it possible to investigate the effects of the main influencing factors
  • demonstrate how these data can be used to provide meaningful indicators of energy performance of buildings (for example expression of energy use for different end uses that are generally applicable among different buildings)
  • develop a methodology for performance prediction of energy saving policies and technologies that includes the influence of a number of related factors
  • development of methodologies and technologies for long term monitoring of the energy use in buildings.

Methodology involving: measurements, diagnostics and statistical analysis and simulations

Participating countries and organizations

  • Austria: Vienna University of Technology
  • Belgium: University of Liège, Catholic University of Leuven (KUL)
  • Canada: Concordia University
  • Denmark: Aalborg University, Technical University of Denmark
  • Finland: VTT Technical Research Centre of Finland
  • France: CETHIL - INSA Lyon
  • Italy: Politecnico di Torino
  • Japan: Tohoku University
  • Norway: Norwegian University of Science and Technology
  • P.R. China: Tsinghua University 
  • The Netherlands: Technical University of Eindhoven, Cauberg-Huygen Raadgevende Ingenieurs BV
  • USA: Lawrence Berkeley National Laboratory


IEA website

ECBCS Program website

IEA ECBCS Annex 53 website

IEA ECBCS Annex 53 - 1st Newsletter


 Philippe ANDRE (Co-Leader Subtask D)

Département des sciences et gestion de l'environnement
Université de Liège
Campus d'Arlon
Avenue du Longwy, 185
B-6700 Arlon
Tel: +32 63 230858
Fax: +32 63 230897

Vincent LEMORT (Co-Leader Subtask D)

Laboratoire de Thermodynamique
Université de Liège
Campus du Sart-Tilman, bât B49
Chemin des Chevreuils
B-4000 Liège

Tel: +32 43 66 48 01
Tel: (Secretariat) +32 43 66 48 00
Fax: +32 43 66 48 12


This work is financially supported by the Walloon Region of Belgium. 


1st preparation phase meeting, Liège, February 2009

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