Integrating economic considerations with operational and embodied emissions into a decision support system for the optimal ranking of building retrofit options

In the UK, 87% of dwellings and 60% of non-domestic buildings that will be standing in 2050 have already been built. Therefore, the greatest energy savings and emissions reductions will be achieved through retrofit of existing buildings. This usually involves decision-making processes targeted at reducing operational energy consumption and maintenance bills. For this reason, retrofit decisions by building stakeholders are typically driven by financial considerations. However, recent trends towards environmentally conscious design and retrofit have focused on the environmental merits of these options, emphasising a lifecycle approach to emissions reduction. Building stakeholders cannot easily quantify and compare the sustainability impacts of retrofit options since they lack the resources to perform an effective decision analysis. In part, this is due to the inadequacy of existing methods to assess and compare the cost, operational performance and environmental merit of the options. Current methods to quantify these parameters are considered in isolation when making decisions about energy conservation in buildings. To effectively manage the reduction of lifecycle environmental impacts, it is necessary to link financial cost with both operational and embodied emissions. This paper presents a robust Decision Support System which integrates economic and net environmental benefits (including embodied and operational emissions) to produce optimal decisions based on marginal abatement cost methods and Pareto optimisation. The implication of the DSS within the current climate change policies is also discussed. Overall, the methodology developed provides stakeholders with an efficient and reliable decision process that is informed by both environmental and financial considerations.