Designing for 40°C summers: how architects are taking on extreme heat in India

For most of modern architecture, heat was the mechanical engineer's problem. Draw the building, then size the air conditioning. That deal is ending. India has officially recognised heatwaves as natural disasters, The Economic Times reported this week, and a National Disaster Management Authority member called the money available for adaptation "inadequate and unpredictable". When the funding is thin, the cheapest cooling is the kind you design in.

The stakes are not abstract

Researchers estimate that heat killed a record 50,000 people in European cities between June and August, The Guardian reported. Warm nights that stopped bodies recovering were part of the damage. That is a lesson for any architect who treats night ventilation as optional.

In India the cost often shows up as lost income. Mahila Housing Trust, an Earthshot Prize 2026 finalist led by civil engineer Bijal Brahmbhatt, works with low income women who were losing 23% of their income to extreme heat, India Today reported. Its tools include cool roofs, climate insurance and community led action. A roof, in other words, is now an economic decision.

Old answers, newly measured

The best heat strategies are rarely new. Parametric Architecture's look at vernacular buildings reminds us that walls, roofs, courtyards, openings and materials handled heat long before air conditioning, through an understanding of sun and airflow. Hiten Kakadiya of Aayam Architects applied that thinking to a well ventilated home in Bhuj designed to stay comfortable in 40°C summers, working with master artisans rather than reaching for Italian marble.

Materials are getting a second look too. Ekarth Studio used bamboo as the primary structure of the 10,000 sq ft Maestro Ilaiyaraaja Center at IIT Madras, completed in 11 months. Parametric Architecture notes that bamboo, long called the poor man's timber, is being treated there as a structural language capable of large spans.

Better numbers for green roofs

Green roofs are a favourite heat fix, but the models behind them have been shaky. A team of Canadian and European researchers rebuilt the green roof physics in a widely used weather model and cut errors in the heat moving through the soil layer by more than 75%, Bioengineer reported. For designers, that means future cooling predictions should be easier to trust, and easier to defend to a client who asks what the extra structure buys.

City data is finally usable

Two Indian cities offered new tools this month. Bhubaneswar unveiled a Climate Digital Twin, billed as India's first interactive climate risk platform for citizens, built by the municipal corporation with technical support from GIZ India. At the first Bangalore Climate Data Week, WRI India launched Data Lab Connect and the Centre for Study of Science, Technology and Policy launched a heat insights explorer. Site analysis used to mean a sun path diagram. It can now mean a street level heat map.

The business case is arriving

Certification bodies are pushing for incentives. The Indian Green Building Council has asked Telangana to give property tax concessions to green certified homes, The New Indian Express reported. Its chairman said 541 of the state's 1,283 registered IGBC buildings save 6.56 billion litres of water a year. The 18th GRIHA Summit opens on 3 November at the India Habitat Centre in Delhi, a good place to hear where policy is heading.

What this means for your practice

Three habits are worth building now. Treat shade, airflow and thermal mass as the first moves, not the decoration. Use the city heat data that now exists, and put it in your drawings. And measure what you build, because a client paying for passive design will want proof. Architects who want to practise this on the ground can try Earth5R's FIELDWORK fellowship, where fellows do real fieldwork and get it independently verified. Heat is not going away. The good news is that architecture already knows a lot about keeping cool.