Turning up the heat

July 10, 2017

Award-winning Passivhaus scheme Wimbish – Hastoe Group

This June, the UK experienced its hottest weather in four decades. Reaching a scorching 35ºC[1], this heatwave is just the latest in an ongoing trend of rising summer temperatures. According to the Met Office the UK’s average temperature has risen by over half a degree over the last two decades[2] and it is projected to keep climbing in future.

0.5ºC may not sound like much and many would argue that they wouldn’t mind a few more hot summer days. But worst-case scenarios predict a 5ºC temperature rise by 2050[3] and this will bring with it some serious challenges, not least of these being the risk of overheating buildings. Dangers associated with overheating range from reduced thermal comfort (resulting in lower productivity) to heatstroke, the exacerbation of existing health conditions and mortalities[4]. The 2003 heatwave resulted in over 2000 deaths in the UK alone[5], and tragedies on this scale are likely to become more frequent if overheating is not tackled at the building level.

At present, the UK’s housing stock is inadequately equipped to adapt to future temperature increases. Safe As Houses, Sustainable Homes’ recent review of sustainability in the UK housing sector, found that just 20% of all social housing is at low risk of overheating. This potentially jeopardises the health and wellbeing of 80% of social housing residents. So, what’s the solution?

One thing is for sure: adaptation and mitigation must go together when reducing the overheating risk. Active cooling like air conditioning may seem like a quick fix but it fails to mitigate against climate change; it is predicted that air conditioning emissions could double by 2030 if it is used as the sole adaptation measure[6]. Instead, ways of tackling the overheating issue need to be sustainable and long-term. Here are Sustainable Homes’ top three suggestions:

Improve current properties

The majority of the UK housing stock has not been designed to combat overheating. There are however some simple measures that housing managers can take to improve their current stock:

  • Solar shading structures can be installed reduce the direct sunlight entering buildings and heating the interior. They can range from shutters and blinds to trees and pergolas[7].
  • Buildings can have their albedo (reflectivity) increased with a light-coloured coating on external surfaces to help keep them cool.
  • Demographic management should be a consideration from the outset. Vulnerable residents, such as the very old and very young, should not be housed in the most susceptible homes. These include single-aspect properties with limited potential for ventilation.

Rethink the design process for new-builds

Developers of new builds should take the overheating risk into account at the design stage, so that the houses built now are able to tolerate temperature rises over the coming decade. Besides aspect and orientation, key considerations should include:

  • Ventilation – windows should be located to enable cross-ventilation[8].
  • Thermal mass – buildings with a high capacity to absorb excess heat can help to keep internal temperatures relatively steady.

Increase support from the top

As the Committee on Climate Change (CCC) recently argued[9], the UK government needs to have a clear strategy for reducing the risks of overheating in new and existing properties. This should include stricter regulations to ensure that adaptation measures really are put in place. An overhaul of the planning system is needed so that it can better support adaptation objectives.

Ultimately, it is fully possible to adapt UK housing so that it is adequately prepared for future climate change. However there is a long way to go. A concerted effort from landlords, developers and policy-makers alike will be needed if we are to ensure our homes remain safe and comfortable during the heatwaves of the future.

Overheating is one of the main issues covered in The Review – Safe as Houses, Sustainability of the social housing sector. This report looked at a range of sustainability issues in housing, including energy efficiency, carbon emissions, flood risk and waste management.

To download the report please click here

 

[1] http://www.climatecentral.org/news/warming-tipped-june-heat-wave-21585
[2] https://www.carbonbrief.org/new-met-office-data-shows-the-united-kingdom-is-warming-in-line-with-global-trends
[3] http://ukclimateprojections.metoffice.gov.uk/
[4] Mavrogianni, A., Davies, P., Chalabi, Z., Wilkinson, P., Kolokotroni, M., & Milner, J. (2009) Space heating demand and heatwave vulnerability: London domestic stock. Building Research & Information
[5] Heat waves in the UK: impacts and public health responses, Research Councils UK
[6] Day, A.R., Jones, P.G. and Maidment, G.G. (2009) Forecasting future cooling demand in London, Energy and Buildings
[7] Gething, B. and Puckett, K. (2013) Design for Climate Change, RIBA Publishing
[8] Tillson, A., Oreszczyn, T. and Palmer, J. (2013) Assessing impacts of summertime overheating: some adaptation strategies, Building Research & Information
[9] Committee on Climate Change’s 2017 Report to Parliament

Cecily Church