Author's personal copy Energy and Buildings 67 (2013) 479–488 Contents lists available at ScienceDirect Energy and Buildings j ourna l ho me page: www.elsevier.com/locate/enbuild Embodied and operational energy for new-build housing: A case study of construction methods in the UK Christopher R. Iddon, Steven K. Firth ∗ Building Energy Research Group School of Civil and Building Engineering, Loughborough University, LE11 3TU, UK a r t i c l e i n f o Article history: Received 21 March 2013 Received in revised form 20 August 2013 Accepted 22 August 2013 Keywords: Embodied carbon Operational carbon UK housing BIM Life cycle assessment Embodied carbon reduction a b s t r a c t In this study a Building Information Model (BIM) tool is developed to simultaneously estimate embodied and operational carbon over a 60 year life span for a typical four bedroom detached house. Using the tool, four different construction scenarios are evaluated, representing a range of current construction methods used in present day UK house building. The results show that cradle-to-gate embodied carbon represents 20–26% of the total 60 year carbon emissions, with operational carbon representing 74–80% of total emissions. Construction scenarios that reduce operational carbon by improving the thermal envelope led to a 1–13% increase in embodied carbon but a 4–5% decrease in operational carbon compared to the basecase construction method. Approaches to reduce embodied carbon in new-build housing are also studied and a 24% reduction is demonstrated through building fabric changes. The study recommends that a universally robust methodology for measuring embodied carbon will enable design decisions to be taken to reduce whole life carbon emissions through improved choice of materials. Due to material changes impacting on the thermal characteristics of a dwelling, and to an extent the structural characteristics, an integrated BIM tool will be essential in quickly establishing whole life carbon impacts during the design stage. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Recognition of the role of anthropogenic carbon dioxide’s impact on climate change in recent years has led to the need for worldwide commitments in reducing carbon dioxide (CO 2 ) and other greenhouse gases. The UK government has legislated for a legally binding 80% reduction in CO 2 emissions compared to 1990 levels by 2050 as part of the 2008 Climate Change Act [1]. The built environment is a major contributor to greenhouse gas emis- sions as a result of construction processes, maintenance and energy associated with building use. The energy use throughout the life- time of a building can be categorised into two distinct stages: (i) embodied energy use, the energy associated with the construction of the building; and (ii) operational energy use, the energy used post-construction once the building is commissioned and occu- pied. In this study embodied energy represents the energy required to source and convert raw materials into the finished product, so called cradle to gate. Emissions from buildings accounted for 35% Abbreviations: CO2e, embodied carbon dioxide equivalent emissions; BIM, build- ing information model; OSB, orientated strand board; SIP, structural insulated panels; SAP, standard assessment procedure; ICE, inventory of carbon and energy; IFC, industry foundation classes; NHBC, national house-building council. ∗ Corresponding author. Tel.: +44 01509 222637. E-mail address: s.k.firth@lboro.ac.uk (S.K. Firth). of total UK greenhouse gas emissions in 2011 [2]. Thus great atten- tion has been placed on the building sector with regard to achieving energy reduction measures that will aid the achievement of the stringent targets of the 2008 Climate Change Act. Such measures include insulation of all lofts and cavity walls by 2015, insulation of 2.3 million solid walls by 2022, replacement of 12.6 million old inefficient boilers by 2022 [2]. Policy, through the form of Building Regulations, is the vehi- cle through which change is currently being instigated with the aim to reduce the operational energy demand of new buildings. This legislative drive is resulting in buildings designed to be more energy efficient, in particular for space heating energy demand through reduced fabric heat losses and reduced infiltration heat losses [3]. The targets currently require net zero operational car- bon emissions for all domestic buildings after 2016 and net zero operational carbon emissions for all new non-domestic buildings after 2019 [4]. As this operational energy use decreases, embod- ied energy use (the energy consumed during the construction phase) will become a greater proportion of the house life cycle carbon emissions. Currently there is no legislation in place to reg- ulate the amount of embodied carbon during the construction of a building, including the carbon required to produce, transport and install the building components. Nonetheless, the recent Gov- ernment Construction Strategy and Government Response to the Low Carbon Construction Innovation and Growth Team identifies embodied carbon as an issue that requires further investigation 0378-7788/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.enbuild.2013.08.041