Beating the Heat In Our Homes

In the world's hottest cities, where summers are brutal and reliable air conditioning isn't a given, the heat at home has become hard to escape. The sun no longer just passes through; it lingers in the glass, the walls, and the spaces between rooms. The air turns heavy and warm, and by noon the thermostat reads what feels like unbearable heat.

In these parts of the world, the question is no longer about the weather outside, but how much of it is being trapped inside. Much of this is driven by the Urban Heat Island Effect, which can raise local temperatures by 5 to 10°C above surrounding areas, especially during heat waves (UNEP's Global Cooling Watch Report, 2025). As the planet continues to warm because of burning oil and gas, it becomes an issue that more of us have to face.

Rising Heat Waves

Heat waves, as we already know, are becoming a more severe natural hazard. For over a decade, there have been approximately 489,000 deaths every year due to heat stress alone, according to the World Health Organisation. Health-related costs are projected to reach around USD 2–4 billion by 2030.

Rising heat reflects failures to mitigate climate change, making adaptation increasingly unavoidable. For many people, that means relying on air conditioners to keep homes cool. As a result, the number of installed air conditioners could triple by 2050, leading to emissions of 7.2 billion tonnes CO₂e, even with energy-efficiency improvements and refrigerant phase-down policies. But many households worldwide cannot afford or obtain air conditioners. The real challenge, then, is how to adapt to the unbearable heat at home while protecting both livelihoods and the environment.

The answer may lie in sustainable solutions such as passive cooling strategies.  The strategies include changing the building orientation, shading, window sizing, and natural ventilation.

Building Codes

Building energy codes help ensure that passive cooling elements are built into structures from the start. These measures include optimized building orientation, double glazing, external shading, and cool roofs.

Pakistan and Kenya have revised their building energy codes, introduced mandatory energy-efficiency measures and emphasized passive cooling (Global Cooling Watch Report, 2025). In fact, optimizing the building envelope and orientation alone can yield energy savings of up to 37% and reduce energy needs by up to 4.5% (World Bank, 2025).

Simple things like planting trees and requiring them with new construction also reduce the Urban Heat Island Effect. Trees provide shade, cool the air, and help absorb heat that would otherwise build up on streets, sidewalks, and buildings. When neighborhoods have more trees and green spaces, they can feel cooler and more comfortable, especially during hot days.

Windows

Upgrading windows—for example, switching from single glazing to double glazing, can cut GHG emissions by 0.07 tCO₂e per m² per year, while improving thermal comfort (Project Drawdown analysis).

Cool and Green Roofs

Cool Roofs Using highly reflective roof colours, such as white or other light shades, can reduce roof surface temperatures. This can also lead to energy savings of 15% for newly constructed buildings (Santamouris et al., 2022). In Ahmedabad, India, a cooling plan helped 7,000 low-income households paint their roofs white (UNEP, 2024). California’s updated building code in 2023 also mandated cool roofs for new buildings to reduce heat-island effects.

Green Roofs Green roofs and green walls can cool buildings while sequestering carbon through photosynthesis, and they can reduce surface temperatures by about 3°C (Wong et al., 2021).

Other passive cooling measures include building shading, optimized window sizing, and the use of water bodies. For example, the Cheonggyecheon Stream in South Korea has reduced surrounding temperatures by 3–5°C, according to the World Economic Forum.

Energy Efficient Solutions

Heat Pump Heat pumps cool efficiently by moving heat rather than “burning” fuels, which can reduce emissions from fossil-based heating and refrigeration. Many countries are already incentivizing heat pumps; for example, the UK aims to install 600,000 heat pumps by 2028 (Zahiri & Gupta, 2023). Canada’s adaptation plans also recommend heat pumps to reduce heat-wave morbidity, according to the Canadian Climate Institute.

Hybrid Cooling Another energy-saving approach is combining ceiling fans with an AC set at an optimal temperature. In Singapore, using a ceiling fan and setting the AC temperature to 26°C led to 32% energy savings while improving thermal comfort (Kent et al., 2023).

Changing Habits to Beat the Heat

To beat the heat, start with habits you can control at home. Open windows strategically to create cross-ventilation and reduce reliance on AC. During the hottest hours (around noon), use blinds to reduce solar heat gain. Add simple, natural support like aloe vera to improve comfort. With hybrid cooling, overall energy consumption can drop by 30% (IEA, 2025), and passive cooling can reduce AC load by up to 80%.