An empirical review of methods to assess overheating in buildings in the context of changes to extreme heat events

Under climate change, extreme heat events are projected to become more frequent and intense. With people spending approximately 90% for their time indoors and buildings having long lifetimes, it is important that the built environment is resilient to these changes. Current methods to assess building performance in a future climate typically use morphed weather files and annual metrics. We compare 30 metrics and 2 weather data sources to assess and improve the representation of extreme heat events in building simulation. We show that morphing an extreme observed year may not necessarily result in an equally extreme year under the future climate and that current annual metrics do not correlate well with heatwave severity. We suggest that weather data from climate models is more robust in representing future weather for the UK and explore the recent UKCP18 data. We propose novel metrics which are able to capture heatwave severity inside buildings.