J. Civil Eng. Architect. Res. Vol. 4, No. 4, 2017, pp. 1975-1983 Received: May 16, 2017, Published: April 25, 2017 Journal of Civil Engineering and Architecture Research Calculated Embodied Energy Intensity of Construction Materials in Typical Hellenic Dwellings Dimitrios G. Koubogiannis 1 , Georgios Syngros 1 and Constantinos A. Balaras 2 1. Department of Energy Technology Engineering, Technological Educational Institute of Athens, Athens GR 12210, Greece 2. Group Energy Conservation, Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Athens GR 15236, Greece Corresponding author: Dimitrios G. Koubogiannis (dkoubog@teiath.gr) Abstract: As current research moves towards life cycle zero energy buildings, it is important to minimize the total energy consumption and environmental impact of a building during its life cycle. Total energy consists of the operational energy and the EE (embodied energy). Both quantities are related to the corresponding operational and Embodied CO 2 (ECO 2 ) that contribute to the greenhouse phenomenon. In the present work, the basic construction materials of four typical Hellenic dwellings are identified and their embodied energy content is estimated by first performing a material analysis and then calculating their EE by means of the corresponding material EE coefficients (MJ/kg). Data from an international database are utilized for the latter due to lack of a comprehensive Hellenic database. Based on the results, practical baseline indicators for the contribution of each material in terms of mass and EE are extracted. Concrete is found to be the dominant material in terms of mass, while steel dominates in terms of EE. In one case, the materials of the major electro-mechanical building installations have also been considered; their contribution in terms of EE proves to be very low compared to that of the construction materials. Finally, EE payback time related to the replacement of building openings in order to upgrade its energy performance is demonstrated in one of the cases. Keywords: Embodied energy, building materials, Hellenic dwellings, energy payback time. 1. Introduction Building energy consumption corresponds to the 40% of the total energy consumption in Europe and about 45% of the CO 2 emissions in the atmosphere which is accountable for the greenhouse effect [1]. The main legislative tool for improving the energy efficiency of the European building stock is the European Directive on the energy performance of buildings (EPBD recast Directive 2010/31/EC). In accordance with it, national efforts focus towards the concept of nearly zero energy buildings by the end of the decade. From a research point of view, LCA (life cycle assessment) of buildings has attracted special interest and is increasingly implemented in research studies concerning issues in building energy during the last years. ISO14040 standard defines LCA principles and framework and ISO14044 describes the relevant requirements and guidelines. ISO14025 prescribes the principles and procedures of EPD (environmental product declaration), i.e., the standardized way of quantifying the environmental impact of a product or system based on the LCA principles. Building life cycle consists of three stages, namely the initial, the operational and the final stage. The total energy consumed during a building life cycle consists of two parts, the OE (operational energy) and the EE (embodied energy). OE refers to the energy consumed by the building during its operational period of life for heating, cooling, ventilation, lighting, hot water, appliances, etc. EE refers to the energy consumption for activities related to the building materials at the three stages of its life. In particular, during initial stage, EE concerns the energy consumption for the extraction