How Ancient Indian Cooling Systems Are Revolutionising Modern Architecture

As India confronts intensifying heatwaves and soaring energy demands, a quiet revolution is transforming its architectural landscape. With temperatures regularly exceeding 45°C in many regions and air conditioning costs contributing to nearly 40% of building energy consumption, the urgency for sustainable cooling solutions has never been greater. Modern architects are increasingly embracing ancient, passive cooling techniques—time-tested methods offering sustainable, low-energy solutions to contemporary climate challenges.

This architectural renaissance is being driven by both environmental necessity and economic pragmatism. Traditional cooling systems, perfected over millennia across India's diverse climatic zones, are proving remarkably effective at reducing indoor temperatures by 6-8°C without consuming electricity. From the sandstone jaalis of Rajasthan to the stepwells of Gujarat, these ingenious designs demonstrate that sophisticated climate control existed long before mechanical air conditioning.

This resurgence represents not merely nostalgic reverence for the past but strategic integration of heritage wisdom with modern design sensibilities, materials, and construction techniques. Contemporary architects are discovering that these ancient methods not only address current sustainability goals but often outperform modern alternatives in terms of both environmental impact and long-term cost effectiveness.

The Science Behind India's Traditional Cooling Masterpieces

India's architectural heritage brims with ingenious cooling strategies tailored to diverse climates. Elements such as jaalis (perforated screens), courtyards, stepwells, and wind catchers were integral to structures designed for thermal comfort without mechanical intervention.

A traditional cooling method Indian architects are reviving in their designs is the 'jaali' lattice screens—a signature feature of later Mughal architecture. The term 'jaali', which means net, is used widely in Islamic architecture in Central and South Asia. Cut and carved from marble or red sandstone in ornamental geometric patterns, jaali became a popular architectural feature in Mughal India between 16th and 18th centuries CE.

These lattice screens use the Venturi effect to cool air. When air flows at a higher speed as it circulates through a narrower passage, it creates negative pressure, causing a partial vacuum that propels the fluid. Jaali is typically installed as an external lattice screen to buildings, and its cross-section usually shows a larger opening on the outside and a smaller opening on the inside. As wind passes through the jaali, it creates a difference in pressure between the interior and exterior of the building, and cools the air as it is compressed and released.

Stepwells, or baolis, are subterranean structures historically serving as water reservoirs and cool retreats during scorching summers. Their design promotes evaporative cooling, maintaining temperatures several degrees lower than surface levels.

For centuries, Indians without access to active cooling methods have been using similar phenomena to cool water in terracotta vessels called 'matka' in many Indic languages. These terracotta vessels have a long history of being used in South Asia to cool water during sweltering summer months, with the earliest fragments found in the region dating back to the Indus Valley civilisation, more than 3,000 years ago.

Terracotta pots were not the only traditional cooling method used by people living in warm, tropical regions. Indians have used traditional cooling methods like sun-shading, lattice screens, arched domed and vaulted ceilings, and evaporative cooling solutions like stepwells to create cooler microclimates in their homes.

Architects are also revisiting courtyards and open spaces within buildings that facilitate cross-ventilation and serve as thermal buffers. These features, once ubiquitous in Indian homes, are being adapted to contemporary urban settings to enhance natural cooling.

Pioneering the Ancient-Modern Design Revolution

At the forefront of this architectural renaissance is CoolAnt, a Delhi-based firm seamlessly blending traditional cooling methods with modern technology. Their signature installations, including the 'Beehive', 'Binary', 'AeroLeaf', and 'Terrabyte', exemplify this fusion.

The 'Beehive' is a modular terracotta-based cooling system inspired by evaporative cooling principles observed in stepwells and water cascades. It comprises cylindrical terracotta cones arranged in a honeycomb pattern, over which water circulates. As water evaporates, it cools the surrounding air, reducing ambient temperatures by 6–8°C without relying on electricity.

CoolAnt's approach is deeply rooted in studying and reinterpreting traditional Indian cooling techniques, incorporating elements like jaalis, courtyards, and stepwells into their designs whilst adapting them for modern use. "Our work is deeply rooted in the study and reinterpretation of traditional Indian cooling techniques such as jaalis, courtyards, and stepwells. These methods were both environmentally responsive and culturally significant, and we see great potential in adapting them for modern-day use," says a representative from CoolAnt.

Beyond design, CoolAnt emphasises sustainability by using local materials like terracotta, which have low embodied energy. Their collaborations with local artisans ensure authenticity whilst preserving traditional craftsmanship. "Working with local artisans, potters, fabricators, and craftspeople has been an integral part of our process. Not only do these collaborations ensure the authenticity of our material use, but they also help preserve traditional knowledge and craft techniques that might otherwise be lost," the representative adds.

Real-World Success Stories: From Bengaluru to Gurugram

Across India, architects are integrating passive cooling methods into contemporary designs, demonstrating the versatility and efficacy of traditional techniques.

A Threshold, an architectural practice based in Bengaluru, has been innovating with recycled terracotta tiles to create passive cooling screens and façades for buildings. Their designs incorporate a technique known as the 'mutual shading principle', which involves casting shadows on exterior walls to reduce direct sunlight and prevent heat absorption. This passive cooling strategy has long been a feature of traditional Rajasthani architecture, particularly in the homes, havelis, and palaces of Jaipur and Jaisalmer, where it was used to combat the intense desert climate.

Similarly, the headquarters of the Punjab Kesari newspaper in New Delhi demonstrates a fusion of age-old architectural traditions with modern design. Conceived by Studio Symbiosis, the structure is enveloped in a perforated white façade made from glass-reinforced concrete, reminiscent of the classic Indian jaali screen. The design aims to maximise natural light, minimise heat gain, and enhance cross-ventilation. The studio's approach has garnered multiple design accolades for its sustainable and context-sensitive innovation.

Another contemporary structure that makes effective use of jaali design is the student accommodation block at St. Andrew's Institute of Technology and Management in Gurugram, India, made by ZED Lab. The building employs the "stack effect", a physics principle in which warm air rises and escapes, drawing in cooler air from below. The rotation angles of each brick in the jaali have been precisely calibrated to reduce solar radiation and minimise heat gain. The jaali façade acts as a thermal shield, cutting direct sunlight by up to 70%. This passive design approach not only improves indoor comfort but also significantly lowers energy consumption. As a result, the building has reduced its reliance on air conditioning by approximately 35%, leading to a noticeable drop in energy costs.

These architects and studios exemplify a growing movement valuing climate-responsive design, integrating age-old wisdom into modern contexts to create sustainable and comfortable living spaces.

Where Heritage Meets Sustainability

Academic research supports the efficacy of traditional cooling methods. Studies demonstrate that passive cooling techniques, such as those employed in stepwells and jaalis, can significantly reduce indoor temperatures. For instance, stone lattices in stepwells have been observed to cool air by 1–2°C, enhancing comfort in hot climates.

Sai Gaurav, a researcher in sustainable architecture at the School of Planning and Architecture (SPA), Delhi, emphasises the need to bridge the gap between traditional knowledge and modern application. "Traditional cooling systems offer valuable insights into sustainable design. By studying and adapting these methods, we can develop innovative solutions that address contemporary climate challenges," she asserts.

The integration of traditional cooling techniques into modern architecture offers environmental benefits whilst fostering cultural continuity. As climate change intensifies, these time-tested methods provide a blueprint for resilient and sustainable design.

The resurgence of ancient cooling systems in modern Indian architecture signifies a harmonious blend of tradition and innovation. By embracing passive cooling techniques, architects are crafting structures that are environmentally sustainable, culturally resonant, and well-suited to India's climatic realities. As the architectural community continues exploring and adapting these methods, they pave the way for a future where heritage and modernity coexist to create comfortable and sustainable living environments.