Evaluating life cycle carbon reductions in healthcare retrofits through a multi-objective optimisation framework

Retrofitting existing buildings is widely regarded as a key strategy for minimising the environmental impact associated with buildings throughout their life cycle. Although significant attention has been given to residential buildings and effective measures have been implemented, non-domestic buildings still require focused efforts to meet the UK’s sustainability targets. The healthcare sector is a major contributor to the existing non-domestic building stock due to its energy-intensive nature. In the UK, the National Health Service (NHS) operates a wide variety of hospital types, making it difficult to develop effective retrofit strategies that are suitable for all. Therefore, a strategic approach to retrofitting that is tailored to the specific needs and preferences of each NHS Trust is essential. This study examines a range of retrofitting measures for deep-plan and tower Hospitals (DPTH) and identifies the optimal design for reducing life cycle carbon emissions while accounting for stakeholder priorities. The results suggest that while certain optimal scenarios are effective in reducing operational energy use, further life cycle assessment (LCA) reveals different scenarios with a greater impact on lowering the building’s life cycle carbon emissions. Hence, additional life cycle carbon assessment is necessary to evaluate the full impacts of the optimal retrofit designs. Practical Application This research offers building services engineers and sustainability consultants with a robust methodology to evaluate HVAC and glazing retrofit strategies for the energy-intensive areas in UK hospitals, aiming to minimise life cycle carbon emissions. By integrating stakeholder priorities into multi-objective optimisation study through multi-criteria decision-making analysis, the research helps practitioners identify retrofit scenarios that deliver significant carbon savings beyond operational energy reductions, supporting the development of more sustainable healthcare buildings.