Heat your home for free with heating provided by a computer server

I couldn't help but think "Bitcoin mining!" Back in 2011 I remember discussions on bitcointalk.org about giving away Bitcoin miners disguised as "heaters" which would, of course, mine for the manufacturer. So the manufacturer gets all the bitcoins without paying for electricity.

Unfortunately this will never work. Space heaters are cheap enough that their price is a non-issue. Plus they are smaller and hotter. http://www.amazon.com/dp/B004AQLUHC is $15, the size of a bread toaster, and 1500W. You can't have this thermal density from a computing device.

This only seems practical in a handful of climates that stay cold throughout the entire year.

Many places that have very cold winters often also have very warm summers. In which case, do you turn the servers off in the summer?

So.....what happens if you don't need heat anymore(in the summer and such)? I always imagined solutions like this as installing a server in a basement and only using the hot air to heat up the house through air ducts - and if not needed just venting the air outside. In the pictures the server looks like a wall-hanging radiator - surely you can't just switch it off if you don't need it?

The Internet Archive already does this; their headquarters on Funston Street in San Francisco is heated by the server banks that run archive.org. (This occasionally makes the building a little too hot, but luckily the Richmond District in SF is usually a fairly cool climate.)

I've been wondering when such a thing would take hold. If we end up with applications amenable to homomorphic encryption, this could be more viable. It could also lead to further changes in the relative economic power of cold regions where electricity is cheap.

The folks at https://www.cloudandheat.com/en/index.html are doing this in Germany.