Can You Heat a Building With Your Body Heat?

Imagine walking onto the street on a summer evening. Suddenly you realise that the temperature has dropped significantly, so much so that you’re freezing! It’s the dementors, you think! They have arrived in the world of muggles for some unfinished business! In a hurry to find shelter from the cold, you see a huge building ahead and decide to enter it. Oh but what is this? A sense of just the right amount of warmth enveloping your body, like a much-needed blanket, as soon as you enter the building. Your frozen toes finally begin to thaw! It’s a busy building with people pouring in and out of its many doors. It almost appears as if the warmth in the lobby is brewing from the many people within it! As if the building has a mind of its own that has decided to shield the humans inside it from the frigid dementors  outside! 

Snap! Back to reality!

Only one of the two fantastical things you read above is actually just a fantasy. No, dementors are not real! As far as we know they exist only in the Harry Potter universe. But believe it or not, buildings that use the excess heat emitted by human bodies to supply underfloor heating, do exist!

Excess body heat

Stockholm central station

First started by a Swedish real estate company by the name of Jernhusen in 2011, the idea of using the heat generated by commuters in a busy building to keep the building warm has caught the attention of many eco-friendly architects, naturalists and public in general across the world. “Part of the appeal of heating buildings with body heat is the delicious simplicity of finding a new way to use old technology (just pipes, pumps and water). Hands down, it’s my favourite form of renewable energy,” writes Diane Ackerman, in the New York Times. It is a known fact that a human body, on an average, radiates 100 watts of excess heat per hour. This heat can add up quickly in confined spaces. Jernhusen worked on the same idea to channel the body heat from the lakhs of commuters passing through Stockholm’s central station to warm the 13-story Kungsbrohuset office building about 100 yards away, across the road.

Kungsbrohuset Office Building, Stockholm, utilizes the body heat of the approximately 2,50,000 commuters everyday at the nearby central station.

“This is old technology being used in a new way. The only difference here is that we’ve shifted energy between two different buildings,” said Klas Johnasson, chief sustainability officer at Jernhusen. If you’re wondering exactly how this works, to describe it briefly, the heat exchangers in the form of pipes,pumps and water stationed at the ventilation system of the central station, convert the excess body heat into hot water. This is then pumped to the heating system in the Kungsbrohuset office building, to keep it warm.

Following their footsteps, architects from across the world have started implementing this eco-friendly warming solutions into their buildings. For example, the Paris Habitat, a public housing property built in  close proximity to a metro station in Paris or the Mall of America in Minnesota, are some of the buildings that will always save you from the sudden chill caused by the dementors pursuing their unfinished business in the world of muggles!

This ordinary-looking building on rue de Beaubourg, Paris gets much of its heat supply from a nearby metro station (Credit: Paris Habitat)

What do you think of human body heat as a source of renewable energy? Which places in India do you think can contribute to this cause? Speaking of heat have you ever wondered why is fire hot? Share your thoughts in the comment section!