Adapting UK dwellings to reduce overheating during heat waves

Project Overview

The work builds on previous research to generate systematic and holistic guidance for retrofitting UK dwellings to reduce overheating risk during heat waves, whilst at the same time minimising winter heating energy and considering the cost of retrofit. An interactive retrofit advice toolkit has been developed, and made publically available (


The emphasis on UK dwelling refurbishment to date has concentrated on reducing energy use and CO2 emissions during the heating season. Climate change projections show an increase in both the frequency and severity of extreme weather events, including heat waves. Future retrofit planning therefore needs to take account of not only winter thermal performance and associated carbon emissions, but also the need to reduce summer overheating to provide a safe and comfortable environment in a changing climate.

Key Objectives

  • To quantify overheating risks of common types of UK dwellings
  • To rank the effectiveness of adaptations (interventions) to reduce dwelling overheating during heat waves
  • To provide holistic guidance taking into account the winter energy consumption and costs as well as summer overheating performances of the adaptations
  • To present the outcome in a user friendly online toolkit


Greater London Authority

Association of British Insurers home

Department of Communities and Local Government

Adaptation and Resilience to Climate Change Coordination Network

Key findings:

External shutters are the single most effective adaptation for most of the house types considered, typically resulting in a 50% reduction in overheating exposure. External insulation consistently outperforms internal insulation, though the latter could be effective as an element of combined adaptations.

Of the dwelling types studied , 1960s top floor flats and 2006 detached houses (Tier 2) experience more than twice as much overheating as Tier 1 dwellings (end and mid-terraced houses, ground floor flats and semi-detached houses). Tier 2 dwellings are "harder to treat" as their overheating exposure could not be eliminated using the passive measures tested and the costs for retrofitting Tier 2 dwellings could be many times higher than those for Tier 1 houses.

Adaptation should be considered together with mitigation, both in design practice and in regulations. If existing houses are retrofitted for energy efficiency, without considering summer use, overheating could increase dramatically.

Overheating exposure can be significantly greater for residents who have to stay at home during the daytime, e.g. elderly or infirm and they should not, where possible, be housed in the most vulnerable dwellings (Tier 2). 


10 publications including - S. M. Porritt, P. C. Cropper, L. Shao and C. I. Goodier (2012) "Ranking of interventions to reduce dwelling overheating during heat waves"; invited paper, Energy & Building, 55 (16-27).

The project output has informed the NHS Heatwave Plan (2012, 2013) and London Adaptation Strategy (2011) and was reported by BBC radio/TV and in the national press (2011, 2013).


This research is funded by the EPSRC (EP/F036442/1), forming one of the five grants of the CREW consortium led by Dr Stephen Hallett, Cranfield University . Dr Chris Goodier, at Loughborough University is CI and Dr Stephen Porritt, IESD, De Montfort University, RF. Their support and contributions are gratefully acknowledged.

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