A scalability decision-making matrix for overheating mitigation strategies in new build homes in the UK

The impact on health from summertime overheating in houses is a growing concern due to climate change–instigated heatwaves and, unintentionally, from energy conservation requirements. In the UK, overheating is addressed in building regulations, providing methods for determining the potential for overheating and non-prescriptive strategies for mitigating risks. Addressing every house individually for overheating risk with individualised strategies can be time-consuming and expensive. Research in overheating tends to be fragmented, and it has mainly focused on design and in-use performance, with little on the home developer’s decision-making affecting overheating through the development process, the cost-effectiveness of solutions and whether they are implementable. This research explores the concept of scalability and its relevance to overheating mitigation strategies in new build developments in the UK focusing on assisting decision-making by creating a scalability decision-making matrix. Scalability is introduced as a requirement of strategies that are easily assessed and applied to the whole development and tailored to the developer’s development process. A mixed method approach was used, including (i) selection of scalability criteria from literature considering: effectiveness, cost, supply chain, home development process and occupants; (ii) dynamic simulation modelling for effectiveness evaluation of cost-effective strategies; and (iii) evaluation workshops with developers for assessing acceptability and validation. The workshops showed that the scalability decision-making matrix facilitates structured, cooperative, and auditable discussions between stakeholders, recording the rationale behind decisions, thus enabling effective and feasible overheating mitigation strategies as well as providing a mechanism for iteration and improvement across successive developments.