Thermal Comfort: Climate Change and the Environmental Design of Buildings in the United Kingdom

A major anticipated impact of climate change on the built environment in the United Kingdom is an increase in the occurrence of overheating in buildings, due to reduced efficacy of the traditional and still widely used method of cooling buildings - comfort ventilation with outside air. As outside temperatures become higher, the potential to provide cooling with comfort ventilation falls off. This paper examines how serious this impact may be under the UKCIP02 climate change scenarios and investigates the implications of two types of adaptive solution: passive cooling measures, as traditionally used in countries with warmer climates, and mechanical cooling ('air conditioning'). A qualitative assessment is made through consideration of building design weather years 'morphed' under the UKCIP02 scenarios. A quantitative investigation is then made through dynamic thermal modelling of three notional case study office buildings under morphed weather years for London, Manchester and Edinburgh for the UKCP02 Medium-High emissions scenario. It is demonstrated that in London, buildings relying on comfort ventilation are likely to become increasingly vulnerable to serious overheating and that advanced passive or mechanical cooling measures will be needed. For Manchester, projected overheating risks in buildings relying on comfort ventilation are still significant but less than for London, whereas for Edinburgh overheating risks are low under the climate scenario data used. The implications of these findings for building design in the UK are discussed.