Are London’s homes ready for a heatwave?

Extreme heat is becoming an increasing problem in London as a result of climate change. The 2022 heatwave saw record temperatures recorded across the UK, with London hitting 40°C that July. The London Assembly Planning and Regeneration Committee is investigating whether London's homes are ready for a heatwave.

To understand how overheating will affect London’s housing stock – and how Londoners experience that – in the short- and long-term, as a result of climate change.  

• In summer 2022, the UK experienced its first-ever Health Security Agency Level 4 heat alert and Met Office Red extreme heat warning. Heatwaves of this severity are projected to become both more frequent and more intense, with forecasts indicating an increasing likelihood of days exceeding 40°C. 

• Around one fifth of UK homes are already overheating in summers. Central London boroughs with greater proportions of flats face higher risks of overheating than outer London boroughs with more houses. By 2050, the Climate Change Committee has projected that heat related deaths may treble without further adaptation actions.  

• Urban areas face heightened overheating risk due to the urban heat island (UHI) effect. In London, temperature differences of up to 7°C have been recorded between urban and surrounding areas.  

• The Mayor commissioned the London Climate Resilience Review, led by Emma Howard-Boyd CBE, in 2023. The review was published in July 2024, with 22 of its 50 recommendations focused on the built environment. The report concluded that “climate change is not sufficiently embedded in decision-making, increasing risks to people and built environment assets.” The Mayor accepted all the recommendations made to City Hall.

• Fewer British homes have air conditioning than in other northern European countries. In 2020, around 5 per cent of British households had air conditioning units, much lower than countries like France (25 per cent), Germany (19 per cent) and the Netherlands (14 per cent).

1. Are London’s homes able to cope with current and projected future overheating risks (in 20–30 years’ time)?  

2. What measures (e.g. shading, dual aspect, air conditioning, retrofit) should new and existing homes in London incorporate to be “heat-proofed” against current and projected future overheating risks? What barriers exist to implementing these measures 

3. Are existing planning and building regulations sufficient to ensure these measures are consistently delivered in practice? What else is needed? 

4. Does a focus on making homes warm in winter risk homes that are too hot in summer? 

5. Is the London Plan’s current stance on air conditioning [Policy SI 4] still appropriate?  

6. What is the impact of building typology on London’s urban heat island effect, and how should this be addressed in future?