Assessment of interventions to reduce dwelling overheating during heat waves considering annual energy use and cost

Climate change projections indicate that the UK is expected to experience more frequent and more intense heat wave periods over the coming decades. Buildings frequently experience overheating even under the present climate, resulting in discomfort, health complaints and even mortality. Current house building rates are low, resulting in a need to adapt the existing building stock to provide more comfortable and safe environments. Dynamic thermal simulation computer modelling was used to assess and rank the effectiveness of selected single and combined interventions (adaptations) in reducing overheating during a heat wave period for a range of dwelling types, orientations and occupancy profiles. It is shown that solar protection interventions, such as window shutters and solar reflective coatings, can be amongst the most effective at reducing overheating during heat wave periods, but with a corresponding increase in annual space heating energy use. Whereas the addition of wall insulation, though beneficial for reducing energy use, may in some cases actually increase summer overheating. The results and guidance are presented in a way that allows identification of parts of the building stock most at risk and rapid selection of the best performing interventions in terms of overheating reduction, cost and annual energy use. It is also shown that above certain cost levels there is a diminishing return in both overheating performance and energy use reduction. The results of this research will provide important information to support refurbishment decisions of both individual house owners and landlords responsible for multiple properties, such as housing associations and local authorities.