Contents lists available at ScienceDirect Sustainable Cities and Society journal homepage: www.elsevier.com/locate/scs Energy and environmental performance based decision support process for early design stages of residential buildings under climate change Mumine Gercek ⁎ , Zeynep Durmuş Arsan Department of Architecture, Izmir Institute of Technology, Urla, Izmir, Turkey ARTICLE INFO Keywords: Residential buildings Building energy and environmental performance Sensitivity analysis Design decision support Climate change ABSTRACT Building design decisions have high impacts on energy and environmental performance of buildings. Especially, conscious decisions in earlier design stages are more significant due to lifespan impact of buildings. Deficiencies in systematic approach for design decision support to increase energy and environmental performance of buildings are projected as the major problems of this study. Decisions for performance-based design should be made in terms of the most effective design parameters peculiar for each project. This study exemplifies the act of design decision support in early design stage of a residential building in Turkey. The relation between design parameters and annual energy consumption for heating, cooling and annual operational CO 2 emissions is ex- amined by global sensitivity analyses for the present, 2020s, 2050s and 2080s weather conditions. Design process requires the assessment of the uncertainties in building performance caused both by design parameters and climate change. The results indicate that the decisions about solar heat gain coefficients (SHGC), and heat transfer coefficients (U) of transparent surfaces on building envelope have the highest impacts on energy and environmental performance of residential buildings in hot-humid climatic conditions. 1. Introduction Increasing energy demand together with environmental problems resulting from global warming and climate change have accelerated the global attraction about energy and environmental issues. These pro- blems are mainly solved by decreasing energy consumption and greenhouse gas (GHG) emissions. Therefore, significant consideration is given to the building sector to diminish the global problems. For in- stance, residential buildings are accounted for 35.11% of energy con- sumption in Turkey (The Ministry of Energy & Natural Resources, 2014). Moreover, the total CO 2 equivalent GHG emissions increased 122% from 1990 to 2015, while energy consumption covers 71.6% of total releases (Turkish Statistical Institute, 2017). It is emphasized that the decisions in earlier stages of design are even more significant to reach projected performance goals (US Energy Information Administration, 2011). The concept of sustainable design has become a global medium, by which architects aim to meet human needs while preserving the en- vironment. Accordingly, many countries have already established laws and institutions towards reducing the effects of climate change, in- creasing energy savings and reducing CO 2 emissions. However, archi- tects, in practice, may not have full of knowledge, or comprehend all parameters simultaneously, since the design and construction are imperfect processes with a variety of inherent uncertainties. Hence, the importance of design decision support arises, as well. The realities of global warming and increasing energy demand have revealed the need for holistic environmental solutions. Building design is a complex process; including not only aesthetical issues but also many factors to be thought to meet physical, environmental and user- centered requirements. The quality criteria for sustainable building design has a wide range from conventional performance indicators to the most recent subjects such as nearly zero energy consumption, en- ergy plus structuring and carbon zero buildings/cities. Many legislative regulations exist to increase the building performance of already ex- isting and new buildings (European Union [EU], 2002). In this sense, there are plenty of very recent studies scrutinizing energy performance assessment. The design decision support approaches are also one of the intensive topics related to the improvement of building energy perfor- mance, especially for early design stages (Tavares & Martins, 2007; Vullo, Passera, & Lollini, 2018). The recent literature on design decision support for architects fo- cuses on the link between two main study areas: professional experi- ences gained from previous works and decision support information provided by the digital analysis tools. Hence, creating a link between professionals and systematic knowledge received from building per- formance simulations has become significant for building design stages https://doi.org/10.1016/j.scs.2019.101580 Received 21 September 2018; Received in revised form 24 February 2019; Accepted 29 April 2019 ⁎ Corresponding author at: Izmir Institute of Technology, Department of Architecture, Block A, Room: 323, 35430, Urla, Izmir, Turkey. E-mail addresses: muminegercek@iyte.edu.tr (M. Gercek), zeynepdurmus@iyte.edu.tr (Z. Durmuş Arsan). Sustainable Cities and Society 48 (2019) 101580 Available online 04 May 2019 2210-6707/ © 2019 Elsevier Ltd. All rights reserved. T