A battleground of climate change: Summer air temperatures in social housing

For social housing tenants, the compounding effects of hotter summers, low-quality buildings, and energy poverty create a high-risk environment with unsafe thermal conditions. The basic human right of indoor thermal safety is generally overlooked by funders, designers, and builders of social housing. This study used empirical data to assess the frequency, intensity, and duration of unsafe indoor air temperatures ( T indoor ) in single-level and multi-storey social housing across Greater Sydney, Australia. Regardless of location or building typology, all households experienced unsafe T indoor during mild summer weather. T indoor ≥ 29 °C was recorded in occupied rooms on up to 58 days in 2022/23, and up to 70 days in 2023/24. T indoor exceeded 35 °C on up to 11 days in 2022/23 and up to 14 days in 2023/24. In an extreme case, T indoor was ≥35 °C for over 11 consecutive hours, peaking at 42 °C. T indoor was related to outdoor air temperatures ( T outdoor ). Depending on building typology, a T outdoor of 30.2–36.8 °C was needed to warm T indoor above 29 °C. Social housing tenants anywhere in Greater Sydney will experience up to twice the current number of days (up to 148 days in the West) with T indoor ≥ 29 °C by 2060. This study highlights the urgent need to address thermal safety in social housing across Greater Sydney. Improved standards for new buildings, alongside engineered and educational heat mitigation strategies for tenants, are urgently needed to prevent exposing vulnerable people to excessive indoor heat.