Any company that’s ever boasted of its green credentials can shove it in the coal burner, after hearing about Helsinki’s Uspenski Cathedral’s data centre, which will use its overheating servers to warm 500 homes joined by a network of pipes.

Opening in January, the centre will save $US563,000 each year and 500 homes will be toasty-warm thanks to the water-heated pipes connecting them to the underground servers. [Reuters and Fast Company]