Energy and environmental assessment of two high energy performance residential buildings Stéphane Thiers * , Bruno Peuportier Center for Energy and Processes, MINES ParisTech, 5 rue Léon Blum, 91120 Palaiseau, France article info Article history: Received 6 July 2011 Received in revised form 23 November 2011 Accepted 24 November 2011 Keywords: Life cycle assessment Positive energy building Zero-energy building Heating system Simulation abstract The «positive energy building 3 concept combines energy saving and electricity production using renewable resources, aiming a positive primary energy balance on a yearly basis. Compared to other concepts of high energy performance buildings, it is very ambitious on an energy point of view, but more materials and components are used, this is why the environmental relevance of this concept has to be questioned. In order to contribute to answer this question, a life cycle assessment (LCA), including the fabrication of components, construction, operation, maintenance, dismantling and waste treatment, has been used to evaluate the environmental impacts of two high energy performance buildings: a renovated multi- family social housing building and two passive attached houses. Both buildings are located in North of France. For the purpose of this study, renewable energy production has been assumed to achieve nearly positive energy balances. For these buildings, four different heating solutions have been studied: an electric heat pump, a wood pellet condensing boiler, a wood pellet micro-cogeneration unit, and district heating. Modeling and simulation have been performed using the building thermal simulation tool COMFIE, to evaluate the heating load and thermal comfort level, and the LCA tool EQUER to evaluate twelve impact indicators. The results show the level of performance as well as the influence of the choice of the heating system on the environmental impacts considered in this assessment. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Energy performance of buildings is today recognized as a major issue to address the worrying questions of human-induced global warming and depletion of fossil energy resources. To this purpose, several high energy performance building (HEPB) concepts have been proposed, from low-energy building through passive building and zero-energy building to positive energy building and even autonomous building. Nowadays a lot of national regulations introduce such concepts as targets for the buildings to be con- structed [1]. In particular, the recast of the European Energy Performance of Buildings Directive (EPBD) [2] targets nearly-zero- energy performance for all new buildings by the end of 2020. Beyond energy issues, high energy performance buildings are supposed to contribute to the reduction of the environmental burden of the building sector. Moreover it seems relevant to consider that the more energy-performing a building is, the less negative environmental impacts it induces. This is surely true during the operation phase of the building, but compared to stan- dard buildings, a HEPB generally requires more material (thicker insulation, triple glazing windows, etc.) and more components (solar panels, etc.) and thus induces more environmental impacts during the other phases of the building life (construction, refur- bishment, demolition). Several previous studies have been per- formed, showing more or less clearly this phenomenon [3e10]. Especially, Feist [7] shows that overall cumulative energy demand (primary energy) can be higher for a self-sufficient solar house than for a passive house due to the production and replacement of the additional technical systems. The aim of this paper is to evaluate the environmental relevance of HEPBs on a life cycle approach, considering more recent life cycle data and impact assessment methods. Definitions are first reminded, then the method is presented and results are provided for two case studies in France. * Corresponding author. Tel.: þ33 169 19 17 02; fax: þ33 169 19 45 01. E-mail address: stephane.thiers@mines-paristech.fr (S. Thiers). Contents lists available at SciVerse ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv 0360-1323/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.buildenv.2011.11.018 Building and Environment 51 (2012) 276e284