Nice article. It certainly works at scale because of the economies. I think this distributed system has potential but there are some issues. There are also some things they could do to make it better if the trial is a success.

Using resistive heating (which is what this is) is not very efficient (even if it's a by-product). A better way to heat your home is to not waste power and use it instead to run an electric heat pump (which are over 100% efficient). There is a good analysis in the "Mythconceptions" section at the end of chapter I.11 of the excellent "Sustainable Energy — without the hot air" [0] on p71 (p84 of the free PDF).

That's the downside but there are some interesting applications. They could enable you to host your own personal cloud on the box in your home. So you know where it is.

You could vary the operating time of the servers so they only operate (or at least only run at 100%) when heating is needed. This could be based on the season, an external temperature sensor or weather data. Processing could migrate between the hemispheres of the world depending on the season.

The load could also be varied based on the local grid demands and power mix. Various real-time data sources are available that report on how green the current energy mix is [1] [2]. You can even just measure the frequency of the electricity to see how well generation is matching consumption. This is known as dynamic demand or demand shaping and you can even be paid by the grid operator for it so it could be a good business model. It would also be nice if they partnered with green power companies that buy their energy from renewable sources.

[0] http://www.withouthotair.com/download.html [1] http://www.earth.org.uk/_gridCarbonIntensityGB.html [2] http://www.gridwatch.templar.co.uk/

There's also one in Stockholm, Sweden owned by Bahnhof AB: http://www.opendistrictheating.com/pilots/bahnhof-thule/ (From the same company that also has the "James Bond Data Center").