Guwahati: In a breakthrough that could reshape how buildings stay cool in India’s sweltering summers, researchers at the Indian Institute of Technology (IIT) Guwahati have developed “smart” bricks that can naturally regulate indoor temperatures, potentially cutting down the need for air conditioning and slashing energy use.
The innovation, led by Prof. Pankaj Kalita and his team, comes at a time when rising temperatures and growing dependence on cooling systems are driving up electricity demand and carbon emissions. Published in the Journal of Energy Storage, the study introduces a new kind of brick embedded with phase change materials (PCMs)—substances that absorb and release heat as they change state.
Unlike conventional bricks that passively transfer heat into buildings, these PCM-infused bricks actively manage it. During the day, when temperatures soar, the material absorbs excess heat as it melts, as temperatures drop, it releases that stored heat, helping maintain a more stable indoor environment. The researchers identified a material known as OM35, ideal for climates ranging between 28°C and 38°C as particularly effective for Indian conditions.
But what makes the innovation truly practical is how the team tackled a long-standing challenge: leakage. PCMs tend to seep out when they melt, limiting their real-world use. To overcome this, the IIT Guwahati team integrated the material with biochar—a carbon-rich substance that acts like a sponge, holding the molten material in place while also improving heat transfer.
The result is a biocomposite-filled Autoclaved Aerated Concrete (AAC) brick that is not only lightweight and strong but also significantly more thermally efficient. Simulations show that walls built with these bricks can reduce indoor temperatures by around 3°C, enough to cut cooling energy demand by 10–20%, depending on building design.
At an estimated cost of Rs 115 to Rs 130 per brick, the technology is already within reach of large-scale adoption, with prices expected to fall further if mass-produced. The team is now exploring commercialisation, potentially through a startup, signalling a move from lab innovation to real-world impact.
Beyond individual homes, the implications are far-reaching. In hot and humid regions, where cooling accounts for a major share of electricity consumption such materials could ease pressure on power grids, reduce peak demand, and lower greenhouse gas emissions.