Extreme Heat and How to Live With It: An Adaptive Comfort Perspective from Kerala

Kerala’s relationship with heat is changing. What was once a predictable cycle of warm days and cooler nights is increasingly punctuated by prolonged heat spells, higher humidity, and reduced nighttime relief. For many households, especially those without access to continuous air-conditioning, this shift is wildly uncomfortable- affecting sleep, productivity, and health.

Climate change has long been framed as a growing, future risk. But the reality we are now experiencing suggests otherwise. Delayed action- whether due to economic constraints, policy gaps, or simple inertia- has accelerated its impacts, resulting in more frequent and intense climatic events across the globe. In this context, it is no longer sufficient to discuss sustainability in abstract terms; we need to engage directly with how our built environment responds to these stresses. This is where building physics becomes essential. At its core, building physics is the study of how buildings interact with their environment- how heat, air, and moisture move through materials and spaces- and how these interactions influence indoor comfort, energy use, and occupant wellbeing.

From a building physics perspective, the key question is not simply “how do we cool spaces?” rather, “how do people adapt to heat, and how can buildings support that adaptation?” This is where the concept of adaptive comfort comes in.

Figure: Designed for comfort- where acoustic control and thermal strategies work together to ease heat, humidity, and that sense of suffocation | Photo Credit: Justin Sebastian Photography

Adaptive comfort is based on the simple idea that thermal comfort is not fixed. People naturally adjust to their environment through behavior, clothing, expectations, and physiology. In Kerala, where the air is warm and heavy with moisture for most of the year, comfort is less about achieving a specific indoor temperature and more about enabling air movement, having the ability to cool down your body through heat dissipation, and gaining control over the immediate environment.

A home that works well in this climate is not necessarily the coldest one. It is the one where you can sit without feeling suffocated, where you can sleep through the night, and where the heat does not build up and linger.

The reason heat feels especially difficult here comes down to two things. The first is humidity. When the air is already full of moisture, sweat does not evaporate easily, and the body struggles to cool itself. The second is poor indoor air movement. Many newer homes are designed in a way that limits cross ventilation, which traps heat and moisture inside. This combination leads to what we experience as “stuffy heat”- the feeling of still, heavy air that makes even moderate temperatures feel exhausting.

The good news is that improving comfort does not always require expensive or structural changes. There are small, immediate actions that can make a noticeable difference.

Air movement is the most effective place to start. A ceiling fan, even on a moderate setting, can make a room feel significantly cooler. If you have pedestal or table fans, placing them in a manner that encourages air to move across the room can help create a breeze. Opening windows on opposite sides of the house during early mornings and evenings can also help flush out trapped heat, even if only for short periods.

Figure: Cross-ventilation enabled through opening windows on opposite sides of the room | Photo Credit: Justin Sebastian Photography

Sunlight is another major contributor to indoor heat. Letting it in unchecked during the afternoon can quickly raise indoor temperatures. Keeping curtains or blinds closed during peak hours helps. Even simple solutions like hanging a light-colored cloth or a temporary bamboo screen over sun-facing windows can reduce heat gain. West- and south-facing windows tend to be the most problematic, especially in the late afternoon.

Figure: Minimise internal heat gains by keeping curtains drawn during peak hours | Photo Credit: Justin Sebastian Photography

Daily routines also play a role. Cooking, ironing, and using certain appliances all add heat indoors. Shifting these activities to early mornings or later in the evening can prevent unnecessary heat build-up during the hottest part of the day. Switching to LED lighting, if not already done, is another small change that reduces internal heat.

Figure: Use of LEDs and minimal artificial lighting in living spaces | Photo Credit: Justin Sebastian Photography

At a more personal level, it helps to focus on cooling the body instead of trying to cool the entire space. Wearing loose cotton clothing, taking quick showers, or even using a damp cloth can provide immediate relief. Staying hydrated is equally important, as it directly affects how we experience heat.

If nights are even slightly cooler, it is worth making use of that window. Opening up the house at night and using fans to move air through can help release the heat that has built up during the day. This can make a noticeable difference the following morning, especially in homes that tend to retain heat.

Figure: Opening windows and doors during nighttime helps regulate indoor temperature | Photo Credit: Justin Sebastian Photography

Once these habits are in place, there are a few small upgrades that can improve comfort further without major construction. External shading like awnings or bamboo blinds can cut down direct heat gain. Reflective coatings on roofs can reduce how much heat is absorbed during the day. Window films can help limit solar gain without blocking light entirely. Even small adjustments to improve airflow, such as adding vents above doors, can make spaces feel less enclosed.

Figure: Verandahs and shaded outdoor spaces act as buffer zones between indoor and outdoor spaces | Photo Credit: Saad Sheji

For those planning renovations or new homes, the approach needs to shift slightly. Orientation becomes important, especially reducing exposure to the harsh southern and western sun. Cross ventilation should not be treated as optional. Verandahs, shaded outdoor spaces, and transitional areas can act as buffers between the indoors and outdoors. Material choices also matter, particularly how much heat they absorb and retain. Adding vegetation strategically can provide shade and help cool the surrounding air.

Figure: Building for the heat- Site-responsive orientation, smart material choice, cross-ventilation, and strategic shading | Photo Credit: Justin Sebastian Photography

All of this points to a larger shift in how we think about comfort. The goal is not to eliminate heat completely. In Kerala, that is neither realistic nor necessary. The aim is to make spaces livable, where heat does not feel overwhelming, and where there are ways to find relief.

Air-conditioning still has its place, especially during extreme conditions. But it works best as a support mechanism rather than the default. Relying entirely on it is not always practical, neither economically nor environmentally.

As heat becomes a more regular part of daily life, resilience will come from a mix of small habits, thoughtful design, and a better understanding of how buildings behave in this climate. Comfort, therefore, needs to be more focused on adaptation. It is about learning how to live with the climate in a way that feels manageable, even on the hottest days.