According to Mathews, the first three to four meters of earth maintain a constant temperature year-round, the average between the land’s maximum and minimum heat.
Published May 12, 2025 | 8:00 AM ⚊ Updated May 12, 2025 | 8:00 AM
Neel Mathews in Let's Talk Water.
Synopsis: Environmental innovator Neel Mathews believes the return on investment (ROI) should be redefined — not just in profits, but in positive impact.
“If it’s good for nature and good for society — that is ROI,” said environmental innovator Neel Mathews, setting the tone for a deeply insightful conversation with Let’s Talk Water host Nolan Pinto. In a country where the majority of people are spiritually inclined, Mathews believes the return on investment (ROI) should be redefined — not just in profits, but in positive impact.
“India has always been a land where people give everything for their children — wealth, time, effort. However, unknowingly, we are also sacrificing nature, leaving behind a damaged world that they’ll be forced to rebuild,” said Mathews.
He warned that while nature can regenerate, it works on its own timeline.
The focus of the conversation was Mathews’ simple use of earth tube cooling, a modern adaptation of ancient wisdom. “This isn’t new technology,” he clarifies. “Our ancestors used it in palaces and temples, often connected through tunnels. They weren’t just escape routes — they had a scientific role. These tunnels carried cool air, utilising the earth’s natural temperature regulation.”
According to Mathews, the first three to four meters of earth maintain a constant temperature year-round, the average between the land’s maximum and minimum heat. Mathews has developed a city-friendly version using basic resources.
“I’ve created a system using two empty water tanks and a well,” he explains. “Cool air from the well enters the first tank, passes to the second, and then is distributed into rooms through air inlets. It keeps the house cool in summer and warm in winter, without relying on electricity.”
This is low-cost, low-maintenance, and highly efficient — a rare mix in the urban sustainability space.
For Mathews, the true ROI isn’t just in lower energy bills or cooler homes. It’s the broader impact — cleaner air, less strain on the grid, healthier living, and the spiritual satisfaction of living in harmony with nature. “We must realign our values. If every Indian believed that doing good for nature and society brings real returns — this country would be the most beautiful place on Earth.”
Watch the full conversation in the podcast:
(Edited by Muhammed Fazil.)
