Computers get hot and data centres use a huge amount of energy to deal with it. Remarkably the waste heat from a large data centre could provide hot water for 11,000 homes. 
But moving heat is hard, it requires new infrastructure or a pre-existing heat network. Moving bits and bytes is easy, so we've taken the servers to where heat is needed, in people's homes.
We harness the heat from compute to provide free hot water for those that need it, turning a compute problem into a social benefit.