Heat-related illnesses occur when environmental heat stress exceeds the body’s physiological limits of heat tolerance. This most often arises when these limits are already constrained by cofactors such as older age, chronic diseases and certain medications.¹ Global heat-related mortality, estimated to be about 489 000 deaths per year,² is predicted to increase substantially as climate change progresses.³

People in housing with poor thermal performance may be exposed to high indoor temperatures, especially in densely built urban settings. Socially isolated people and those with limited mobility are often unable to engage in heat-avoidance behaviours.¹

We urgently need low-cost, energy-efficient, and effective cooling interventions that can be implemented at scale to reduce heat-related health impacts.