October 2015: The Mayor’s has published a set of “good practice cooling energy demand benchmarks for typical apartment dwelling types, based on reasonable design measures”.
The work was undertaken by AECOM for the GLA and supports the London Plan’s cooling hierarchy as set out in Policy 5.9 of Chapter 5 of the London Plan (London’s Response to Climate Change) which states the following [page 200 onwards]:
Major development proposals should reduce potential overheating and reliance on air conditioning systems and demonstrate this in accordance with the following cooling hierarchy:
- minimise internal heat generation through energy efficient design
- reduce the amount of heat entering a building in summer through orientation, shading, albedo, fenestration, insulation and green roofs and walls
- manage the heat within the building through exposed internal thermal mass and high ceilings
- passive ventilation
- mechanical ventilation
- active cooling systems (ensuring they are the lowest carbon options).
Two case studies where overheating in London developments has been identified are referenced in the study, including the Seagar Distillery redevelopment in Lewisham, as well as a paper, Forecasting future cooling demand in London, which estimates that the London residential sector could be responsible for an extra 100,000 tonnes CO2 per year by 2030 as a result of cooling.
A number of conclusions and recommendations are made in the study (p60 onwards) including:
- GLA could produce a checklist for developers to complete with information about glazing ratios, shading methods, ventilation options etc. to help determine whether the development is likely to have overheating problems that should be investigated further. It could be used to identify when detailed modelling is required and could help monitor typical responses to the cooling hierarchy.