How architects are rethinking housing design to address rising heat in Indian cities

“The basement footprint was reduced to minimise concrete consumption while increasing ground-level green spaces. Since basements are typically the most concrete-intensive component of a residence, this significantly lowered the embodied carbon of the project while enhancing landscape coverage,” Siripurapu adds.

If the upfront cost of installing these systems increases the investment by 5-10%, the material and construction spends remain comparable to, if not cheaper than, that of a similar house.

Some of these innovations have caused delays. Sourcing quality green cement (which is engineered to deliver the same structural performance as conventional cement while lowering CO2 emissions by reducing clinker content and using materials like fly ash, slag, or calcined clay) is not easy. “We had to wait for a month before we could cast,” Siripurapu says.

But Haider is not complaining. “I want my home to be as close to (the German concept of) a ‘passive house’ as possible,” he says, aware of the intricacies involved in executing such a building. In the late 1980s, German physicist Wolfgang Feist and Swedish structural engineer Bo Adamson put out the idea that a building should be designed and insulated in such a way that it can maintain a comfortable indoor temperature entirely “passively”, without relying on mechanical heating and cooling systems. That is, of course, the ideal scenario.

In the real world, natural cooling solutions cannot work all the time on their own, especially in extreme hot and dry or humid climates, like in India, without mechanical interventions like air-conditioning. The Haider residence uses a hybrid cooling approach comprising a central air-conditioning system supplemented with split AC units in select spaces. It has a passive cooling envelope—which includes terracotta tile cladding, high-performance double glazing, insulated roof construction, and high solar reflectance exterior coatings—to reduce the cooling load by an estimated 53.75%.

The air-purification principle also contributes to the overall cooling of the house. “Traditionally, people prefer natural ventilation, which is a killer for me because of the high pollution levels (in NCR),” Haider says. So Siripurapu and his team decided to treat the central staircase like a wind catcher, using evaporative cooling screens on all sides to draw cooler air into common spaces such as the courtyard. An exhaust system extracts warm air from the wind catcher and routes it through a Heat Recovery Ventilator (HRV) equipped with HEPA filters. The HRV acts as a central air distribution system by filtering incoming fresh air, recovering cooling energy to bring it close to indoor temperatures, and distributing it throughout the house, thereby improving both energy efficiency and indoor air quality.

The entire blueprint for this system was created by studying heat maps of the site at different times of the day, while also considering simulations of seasonal variations, with the help of a team of energy consultants. “The idea is to make the building modern, elegant, and artistic, while following all the compliance requirements,” says Siripurapu.

LIFE IN A GLASS OVEN

Haider has gone the extra mile to “experiment with the architects,” as he puts it, in the pursuit of building his ideal home—and he isn’t an outlier. As global warming worsens each year, and extreme climate events cause havoc around the world, architects, developers and homeowners are being forced to rethink their priorities and focus on building more climate-resilient living spaces.

The impact of the recent heatwaves has been staggering, not only in tropical South Asia but also in the more temperate regions of Europe. On 23 June, with temperatures soaring above 40 degrees Celsius, France recorded 40 deaths due to drowning as people tried to cool off by swimming in “unsupervised areas”. A report in The Guardian pointed out that “about 66% of French people struggle to tolerate the heat in their homes”, while Paris, which is one of the most densely populated cities in Europe, has the highest heatwave mortality risk among any other capital on the continent because houses in the city were not built for extreme summers.

In the Global South, the numbers are more alarming. A recent study by Piyush Narang and Ashok Gadgil from the India Energy and Climate Center at the University of California Berkeley, pointed out that “a single day of extreme heat causes about 3,400 excess deaths across India.” As The Hindu reported on their findings on 29 May, “Uttar Pradesh alone accounts for about 8,100 excess deaths during a five-day heatwave, while excess deaths in districts, including Ahmedabad, Jaipur and Surat, each exceed 250 in a single event.”

The summer of 2026 has been punishing for urban India in general. In April, Maharashtra issued multiple heatwave alerts in Mumbai and its adjoining areas. Bengaluru, where residents once boasted of not requiring air-conditioning at all, buckled under extreme temperatures from March to May. Delhi experienced an intense heatwave in the last week of June. Although the city’s maximum temperatures hovered around 41.3 degrees Celsius, which is 4.1 degrees Celsius higher than the normal temperature for this time of the year according to the India Meteorological Department, the “real feel” was 51.3 degrees Celsius.

The main reason behind this spike in temperature, scientists at the Indian Institute of Science (IISc) in Bengaluru have shown, is linked to the development of “heat archipelagos”—clusters of extreme heat pockets that merge with one another—in Indian cities. Each archipelago is made up of 50-70 Urban Heat Islands (UHIs), which are areas that are much warmer than their surroundings due to concrete structures, paved surfaces, and glass facades.

“We have mindlessly copied the glass-fronted buildings of the West, which are meant for a very different climate,” says scientist T.V. Ramachandra, one of the co-authors of a research paper published in April. “Glass absorbs heat and increases the consumption of electricity needed to cool a building. This, in turn, leads to higher bills and emission of greenhouse gases.”

Along with shrinking green cover and destruction of a robust system of lakes that once fed the city, Bengaluru’s land profile has undergone a drastic transformation in the last few decades. As Ramachandra and his team pointed out, the built-up and paved area of the city has shot up dramatically, from 8% in 1973 to 87.6% in 2025. Far from being unique to Bengaluru, such shifts are pervasive across India.

“The problem is we do not look at climate at the time of design,” says Sonali Rastogi, co-founder of the Delhi-based architectural firm Morphogenesis. “Instead, we get all caught up in number crunching, ease of land acquisition, and so on. Then, as we start building, we want to mitigate, whereas mitigation should happen at the time of conception.”

Using glass in buildings isn’t a problem by itself. On the contrary, it is an excellent material that helps mentally connect the inside with the outside and bring natural light into our living spaces. “However, there has to be a science behind the way we use glass so that it does not turn a building into an oven,” Rastogi says. “For years, we have used it rampantly without understanding that glass comes in hundreds of varieties, each of which should be used for different expected performances.”

In cities like Mumbai, where apartments tend to be densely packed next to each other, it is often critical to use glass to bring in natural light. “We have to balance several factors—from making sure that the orientation of the building is correct to the amount of sunshade protection that is being planned for it,” says Anshu Shukla, chief design officer at Mahindra Lifespaces Developers Ltd (MLDL).

Planning with such attention to detail at the concept stage has made legacy builders like MLDL more mindful of the climate they are building for. “We can no longer go by the orientation and placement of international buildings. We must make our projects more vernacular, work with materials and styles suited to the Indian climate,” Shukla adds. For example, instead of planting palm trees to imbibe a Dubai-style exclusivity, builders should be opting for native species like neem or gulmohar. “We need large-canopy trees that bring in shade while minimising their need for water,” she says.

This prudent synthesis of common sense and modern science can become a gamechanger for public spaces, too. “I’m not against building a 16-lane highway. But think about designing it in such a way so that at least part of it can be shaded,” Rastogi says. “Such principles are based on laws of physics that have been followed for hundreds of years. This is elementary stuff that is taught to undergraduate students of architecture and needs to come back into the mainframe of our thought process.”

DON’T REINVENT THE WHEEL

In the last few years, vernacular home-cooling techniques—inspired by jalis (screens), baolis (stepwells), chajjas (sunshades) and open courtyards—have made a comeback into modernist design. These elements stand out for their aesthetic appeal while also winning brownie points for sustainability.

The legacy goes back to visionary architects like Laurie Baker, whose signature style was to leave gaps at regular intervals on brick walls to simulate jaali-like structures that helped regulate the flow of natural light and thermal conditions without incurring extra costs. A new generation of designers and architects, like Sandeep Khosla of the Bengaluru-based Khosla+Anand and Gurmeet Akali of the Goa-based Studio Momo, are breathing new life into these traditional elements.

In their contemporary iteration, these forms can yield extremely precise and optimal results because of the cutting-edge technology that is now available. Gurugram-based Soga Design Studio, founded by the husband-wife duo Gajender Sharma and Sonali Jaiswal in 2018, combines vernacular knowledge with parametric and computational design to build a range of products, from facades of buildings to interior design elements, at the intersection of art and technology. “Like a sketchbook or AutoCAD software, parametric design is a tool,” Sharma says. “We can use it to write a code and generate a set of rules that can reveal innumerable possibilities and limitations in a design.”

Parametric design, pioneered by architects like Zaha Hadid, has been called the excel spreadsheet of design, capable of working with many variables. Once you set the rules and relationship—for example, window size should shrink as the sun exposure on one side of the building increases—it can give you numerous design iterations in minutes.

This tool can come in especially handy while designing for heat mitigation. Take, for instance, a variation of wall thickness or height. “Using parametric design, we can get 10,000 different options for what such a variation may mean to all the other components—from time of delivery to budget and everything in between—of a project,” Sharma adds.

Jaiswal pulls up a project at a gurdwara in Mumbai they have worked on as an illustration. “The client didn’t want to install an AC in the prayer and congregation area,” she says. “They wanted to put a screen there to ensure peace and quiet, but also needed the area to stay cool.” Soga Design Studio’s solution was to create a “two-wall system”. “We suggested a larger opening on the outer part and a smaller one in the inner part,” Jaiswal adds. This strategy helps the hot air going in to cool down by the time it goes inside.

Recently Soga Design Studio worked as facade consultants for the refurbished Kapali Mall in Bengaluru. In its earlier avatar as a glass-heavy structure with bulky exterior materials, the building turned into a hothouse. Soga Design Studio proposed a secondary metal skin to reduce material wastage during fabrication as part of their sustainable solution. It does not allow direct daylight penetration, reduces heat gain and, therefore, the cooling load on the system. There is room for the air to flow through the building and act as an insulator.

“Air is the best insulator,” Rastogi agrees. “In my own home in Delhi, I have built a double roof with an air cavity in between. It’s a concept we’ve had since time immemorial, and it doesn’t cost anything.” With four generations of her family living in it, it’s a sizeable house, which has been designed to be climate resilient. “If I leave out one month of extreme humidity, I can do without a fan most of the time,” she says. “I’m not saying I’d be hugely comfortable, but unlike most homes, you won’t be hit by a blast furnace as soon as you enter the space. It is usually 8–9 degrees cooler without any air-conditioning compared to a building of similar size.”

It all boils down to basic architectural science. Every material in a building, Rastogi adds, has its U-value (technically called thermal transmittance), which is used to measure how effective any wall, roof, window, or floor is at preventing heat from transferring through it. “If you don’t study the U-value, you are likely to make the mistake of letting the heat radiate inside, and then you have to crank down the AC to 18 degrees to get some sleep.”

RETURN TO NATURE

Sceptics may argue that the vernacular building technologies of our ancestors worked because the climate crisis wasn’t in the dire straits it is in now. However, as Siripurapu says, “the laws of thermodynamics don’t change,” nor do the evergreen principles on which nature has always operated.

Ten years ago, when he started Ant Studio, Siripurapu wanted to bring together elements of biophilic design and the natural sciences to create solutions for an environmentally vulnerable and volatile world. Ant Studio launched its first product, Beehive, as the covid-19 pandemic was coming to an end. Made of terracotta, it is a modular façade of cylindrical pot-like structures that combines principles of evaporative cooling with the Venturi Effect (if you compress air and let it expand, it begins to cool).

In the years that followed, Siripurapu and his team came up with products like Terrabyte, which uses debris as raw material, binary (a mix of vertical tiles and circular points to simulate binary language), and Aeroleaf, an engineered tile—all of which operate on the principle of evaporative cooling.

“Using the wet bulb depression principle (the lowest temperature air can reach by evaporating water into it), we are able to get the temperature down by up to 10 degrees,” Siripurapu says. Which means when the outside temperature is a scorching 42 degrees, using these products as a primary or secondary facade can bring the inside temperature down to around 30 degrees.

The proof of the pudding is evident as we sit inside Siripurapu’s office in Noida. At 34 degrees, it’s not an unbearably hot day by NCR standards, but the sun is beating down, and the air feels sticky outside. Inside the office, though, which has no AC, it’s cool and comfortable with just a couple of fans on.

“We do warn our clients that with nature-based cooling systems, they may not be able to get a 100% alternative to using air-conditioners,” Siripurapu says. “The limitation of thermodynamics is that as humidity increases, the wet bulb effect starts getting weaker.” As a result, during the monsoon, as the building reaches peak temperature around 3-4pm, the heavy humidity in the air can make the same room we are sitting in feel uncomfortable.

As a counter-strategy, Ant Studio has attempted innovative strategies, such as pre-cooling a space with the help of their products instead of trying to design a one-size-fits-all solution. “Recently we got an inquiry from a cold storage unit, which is being built in Odisha,” Siripurapu says. “For such a hot and humid climate, the set-up will require a tremendous amount of cooling.” While it may be impossible to make nature-based solutions work at such a large scale, the principles behind these approaches can still help optimise the performance of the unit by pre-cooling the air to around 30 degrees, thereby reducing the energy drain. “Even if we improve the performance by 10-20%, it can lead to massive reduction in costs, both in terms of electricity bills and emissions,” Siripurapu says. “Nature-based solutions need not always be the forerunner.”

Further north from Ant Studio, in Rishikesh, Uttarakhand, brothers Raghav and Ansh Kumar are thinking along similar lines as they build their enterprise, Tiny Farm Lab (TFL), drawing on biophilic design and biomimicry (the art of solving human problems by using time-tested knowledge found in nature). “Society treats air-conditioning as an engineering problem, but it is primarily a design problem,” Raghav says. “Our present troubles stem from the fact that we haven’t been building in a bio-regional manner.”

Formerly employed with a German multinational company, the architect set up TFL in 2021. The idea was to focus on natural materials like mud and cob, especially on their thermal mass insulation properties, to build houses that are modern, comfortable and look beautiful. So far, TFL has done projects in Uttarakhand, Madhya Pradesh and Uttar Pradesh.

“It is important for us that the building, instead of adding to the carbon footprint, goes back to the Earth at the end of its life cycle,” Ansh says. The brothers studied behaviours and patterns in the animal kingdom to understand the workings of natural systems. “You can learn much about HVAC systems, passive ventilation, thermal mass, and dynamic regulation by studying a termite mound,” Raghav adds.

After recently winning a Godrej Design Lab Fellowship, the brothers are experimenting with straw as a raw material (they want to explore hemp and lime in the future), but they are not averse to using industrial material in conjunction with natural ones. “We believe no material is bad. It all depends on how much and where you use it,” Raghav says. For now, though, their ideas are confined to rural areas. “There is no doubt about the capabilities of these materials and their biodegradability, but right now we do not have the laws, policies and awareness to replicate these ideas in urban areas,” he adds.

It is still possible, though, to adapt the “founding principles” behind these materials to create “tiny solutions” for the way we build and live. “Even if the buildings are red brick concrete, can we go for earthen plasters? Can we go for lime plasters? How are we shading buildings? There needs to be a toolkit of solutions that can help builders use these principles in urban areas, too,” Raghav says.

BREAK THE SILOS

The challenge of heat mitigation in urban India cannot be solved by architectural innovation alone. Every expert who spoke in this story apportioned a major part of the blame to India’s current urban planning policies. “There’s still a legacy of working in silos—the kinds we saw in the 1960s and 70s, where each entity, from public works to horticulture, played its part without much visibility into the project’s overall impact.” Rastogi says.

Sharma and Jaiswal, who began their professional journey in Singapore in 2017, speak highly of the colour-coded urban planning system that has transformed the island nation into a global model. In this system, managed by the Urban Redevelopment Authority, grey (utility, housing, infrastructure), blue (commercial and mixed-use developments), red (civic and community), and green (nature, recreational) zones represent a highly structured policy designed to maximise the utility of the city-state’s limited land. By creating this framework, planning and architecture has been integrated in the service of making human lives easy and efficient. Admittedly, Singapore is much smaller in size compared to India, so it is perhaps easier to implement such ideas. But India needs to make a start somewhere.

At present, the priorities in the country remain skewed towards money and optics. “It’s common to hear clients say, ‘Line up the buildings this way because our marketing team feels it will sell well’,” Rastogi says. “Sometimes visibility from the highway ends up getting prioritised over thermal comfort, and that’s a trade-off worth questioning.” Clients also tend to push back on key decisions, like wall thickness, wanting it reduced to increase the built-up area, because such choices must have a payback. “The payback is often seen only in terms of the price at which the building can be sold, when, actually, the payback is instant,” she adds. “If you have thicker walls and shading, you need lesser air-conditioning. If you have lesser air-conditioning, you have lesser use for installed electrical power.”

When Morphogenesis was set up in 1996, Rastogi says, “going green”, to most clients, would mean putting Astroturf on the roof. It has taken years to shift this mindset but there is still a long way to go. “There is a growing realisation of the value of green buildings, though we need to keep highlighting the benefits of working and living in such spaces,” adds Shukla. MLDL’s green-certified portfolio include buildings with water recycling, sustainable materials and energy efficiency. If they come at a premium upfront price, the long-term payback of reduced environmental and carbon footprint is likely to even the balance.

However, the green certification policy addresses the problem of energy inefficiency only partially. According to the government’s Energy Performance Index, defined as the annual energy consumption of a building divided by its total built-up area, if a building hits a certain threshold, it is deemed green-rated. But many firms like Morphogenesis, Rastogi points out, always aim to hit 50% lesser than even this stipulated number. “If I can figure out a way to use lesser energy, I should do it, right?” she says. The problem is, if your rating is a five star already, it can’t become a six or seven star, and so, there is no longer any incentive for you to reduce energy consumption further. A policy that looks good on paper isn’t necessarily the best policy.

After Morphogenesis finished building the Surat Diamond Bourse, the world’s largest office building, in 2023, Rastogi says she became aware of the irony of this achievement. The project drew worldwide acclaim, numerous prime-time television channels from far and wide lavished attention on it. But there was little interest in one of its most impressive features, which should have been turned into a popular case study.

“Instead of being an energy guzzler, the Surat Diamond Bourse has a 50% reduction in energy consumption compared to the highest green rating standards,” Rastogi says. “Yet, much of the media coverage focused on it being the world’s largest office building, and the sustainability story didn’t get the same spotlight.” It is this “optics over benefits” approach in every sphere, including the way we live now, that has brought the world to its current state of crisis.