The Planning and Regeneration Committee convened to discuss London's readiness for heatwaves, with a particular focus on housing stock and planning policies. Key discussions revolved around the effectiveness of passive cooling measures, the role of active cooling technologies like air conditioning, and the challenges of retrofitting existing homes and designing new ones to withstand rising temperatures. The committee also explored the disproportionate impact of overheating on vulnerable populations and the need for improved data, communication, and policy interventions to address these issues.

Overheating Risks and Vulnerabilities in London

The committee heard that London faces significant and growing risks from overheating, exacerbated by the urban heat island effect, an ageing population, and existing socio-economic inequalities. Dr Anastasia Milona of the Chartered Institution of Building Services Engineers (CIBSE) highlighted that while new homes are designed to meet certain overheating standards, there is a lack of real-world monitoring data to confirm their effectiveness. David Strong, Design Director at Peabody, noted that while their older Victorian stock often performs better due to thermal mass, newer buildings can be more vulnerable if not designed with overheating in mind. Antonietta Cantor from Arup London emphasised that while passive measures are crucial, a balance with active cooling might be necessary, particularly for vulnerable individuals, though affordability remains a significant concern.

The disproportionate impact of heat on vulnerable groups was a recurring theme. Assembly Member Benali Hamdache raised concerns about the affordability and maintenance of air conditioning for those who need it most. Dr Mehri Khosravi from the University of East London presented research indicating that a significant portion of social housing is at high risk of overheating, and that renters often have less agency to implement cooling solutions. Emma Howard Boyd CBE, former Chair of the London Resilience Review, stressed that existing housing stock is already overheating, even in mild summers, and that failing to address this now will lead to greater costs and vulnerabilities in the future.

Design and Policy Responses to Overheating

A central point of discussion was the effectiveness of the current cooling hierarchy and Building Regulations, particularly Approved Document O (Part O). Tom Dollard of Pollard Thomas Edwards argued that the cooling hierarchy is not being enforced, with many designs jumping straight to ventilation rather than prioritising passive measures like external shading and managing internal gains. Dr Milona agreed that enforcement is the key issue, suggesting that the current regulations leave room for interpretation and that planners need to scrutinise applications more rigorously.

Joel Callow of Beyond Carbon presented a compelling case for Passivhaus-certified apartments combined with exhaust air heat pumps as a cost-effective solution that addresses heating, cooling, and hot water needs while significantly reducing energy costs and carbon emissions. He argued that current regulations, particularly regarding district heating and daylight requirements, can inadvertently hinder effective design and contribute to overheating.

The role of the London Plan and its policies, such as SI4 on the cooling hierarchy, was debated. Jules Pipe CBE, Deputy Mayor for Planning, Regeneration and the Fire Service, clarified that there is no ban on air conditioning in the London Plan, but it requires passive measures to be maximised first. He acknowledged that the modelling used for new developments needs to be more forward-looking and potentially more pessimistic to account for increasing temperatures. Andrew Boff AM questioned whether greening policies are keeping pace with the scale of the challenge and whether the drive for more homes might be prioritising quantity over the quality of cool homes.

Improving Data and Communication

The need for better data on overheating was highlighted by multiple speakers. Polly Turton of Shade the UK called for more real-time monitoring of indoor and outdoor temperatures and suggested an overheating index for homes, similar to Energy Performance Certificates (EPCs). Dr Khosravi echoed this, emphasising the lack of data on high-risk settings like hospitals and care homes, and the need for visible data to prioritise action. Emma Howard Boyd CBE cautioned against delaying action while calling for more data, noting that significant information already exists and can be pooled from various sources, such as social housing providers.

The effectiveness of communication strategies was also discussed. Lord Bailey of Paddington AM questioned the Mayor's role in disseminating information about heat risks, noting his own lack of awareness of heat health alerts. Dr Khosravi presented research showing a significant information gap, with millions of Londoners not being exposed to heat alerts, particularly the elderly and low-income groups. She advocated for community-based interventions to bridge this gap. Emma Howard Boyd CBE suggested learning from other cities that name heatwaves, like Seville, to create a sense of urgency and clarity, and proposed using arts and culture, as well as sports, to engage the public.

Policy and Future Actions

The committee heard that the GLA is developing a London Heat Risk Delivery Plan, expected to be published in summer 2026. Dan Bicknell, Climate Adaptation Manager at the GLA, described it as a vision and a call to action that will convene various sectors to accelerate adaptation. He acknowledged the significant funding gap for retrofitting existing homes, which house the majority of Londoners, and stressed the importance of targeting efforts in areas of greatest risk and need.

Several recommendations were made for future policy. Joel Callow urged the London Plan to explicitly reference the Passivhaus standard as a deemed to comply measure for energy and overheating. Matthew Scott of the Chartered Institute of Housing (CIH) called for Part O of the Building Regulations to be applied to homes created through material change of use, such as office-to-flat conversions, which are currently exempt. He also suggested the need for a hot weather payment to support those struggling with cooling costs, similar to winter fuel payments. Dr Anna Mavrogianni emphasised the need for integrated mitigation and adaptation strategies, with clear leadership from the Mayor to coordinate efforts across different departments and sectors. Ed Hezlet from the Centre for British Progress suggested a pragmatic approach, arguing that as the electricity grid becomes cleaner, the use of active cooling might become less of a concern, and that focusing on efficient systems and managing peak demand is key.

The committee also discussed the potential for an EPC-style assessment for heat risk, which Assembly Member Clark raised. While not currently a focus for the GLA's climate team, it was acknowledged as a potentially valuable tool for informing consumers and planning decisions.

The meeting concluded with a note that the committee's work programme includes further activity, including an informal meeting with the Met Office on 1 June 2026. The next formal meeting was scheduled for 8 July 2026.