Every time you stream a film, scroll online, or ask an AI a question, huge data centres burn power and throw off loads of waste heat.

That heat could warm thousands of homes.

And the tech to reuse it already exists.

Finland is showing what’s possible. Microsoft’s vast site near Helsinki is set to become the world’s biggest heat-recovery project. When fully running next year, it will provide up to 40% of the district heating for hundreds of thousands of flats—using server heat instead of gas or coal. It could cut 2–3% of Finland’s national emissions goal all on its own.

Sweden has done this for years. Stockholm Data Parks already use heat from many data centres to warm local areas.

Denmark does it too—Meta’s site sends out 100,000 MWh of heat each year.

London has now approved a major scheme that will warm more than 9,000 homes from nearby servers.

The tech works. The sums work—especially in cold places.

Yet most of the world still wastes this heat.

And here’s the big point: AI use is exploding. Data centres are being built at record speed.

We should use their heat, not throw it away.