Another day, another bitcoin scam. This time the culprit is an outfit called Butterfly Labs that charged would-be bitcoin miners $149 to $29,899 for mining rigs "specialized computer equipment set up to harvest bitcoin" but then delivered worthless machines late or not at all.

The details of the caper are set out in an announcement from the Federal Trade Commission in which the agency says it obtained a court order to shut down the Butterfly gang, who apparently fleeced nearly 20,000 customers, and spent much of their money on guns and saunas.

As the FTC explains, Butterfly Labs promised to deliver special 'Bitforce' computers for mining bitcoins. Unfortunately for the customers, "the passage of time rendered some of their machines as effective as a 'room heater' " (perhaps giving new meaning to the term 'boiler room').
...

Heat Your House with Someone Else's Computers

Data centers have no use for all of the waste heat that they generate, but there are plenty of situations in which waste heat isn't wasted at all: say, inside your house, in the middle of winter, especially if you live somewhere cold. The obvious solution here is to just live in a data center and bask in its warmth, or slightly less ridiculously, put a very small data center in your home or office that generates a useful amount of heat on demand.

In 2011, Microsoft Research published a paper [PDF] suggesting that it might make a lot of sense (i.e. be commercially viable) to use cloud computing servers installed in homes and offices to provide inexpensive, efficient heat and hot water.

The consumer wins because they get free heat, and the cloud computing company wins because they don't have to build and maintain huge data centers. This "data furnace" concept seems like the proverbial win-win, and several different companies have started trying to make it happen.

It seems like the notion of heating ones house with residual heat from Bitcoin mining has been around for a long term, see slashdot

http://bitcoin.stackexchange.com/questions/2283/can-i-use-bitcoin-mining-as-a-data-furnace-to-heat-my-home

from 2011.12.21 and also FTAlphaville from 2014.09.05

http://www.forodeforos.org/uploads/notepierdas/d5715aa07eff32ec875970ec3ad6915ea3ec01ec.pdf

which calls it "the latest fad." Vitalik Buterin also spotted the security argument in 2012.02.28

"If miners figure out that they can dual-use their mining electricity by making their computers heat their homes during the winter, that would be a very positive change since it would decentralize mining to something every home or business does rather than a task done by centralized, specialized supercomputers and it would increase the network's hash power and thus security but it would not ultimately reduce the mining cost."

https://bitcoinmagazine.com/96/the-wasted-electricity-objection-to-bitcoin/

This comment all on the back of FtAlpahville's piece revealing that now 21Inc (formerly 21e6) are doing exactly that:

"Its core business plan it turns out will be embedding ASIC bitcoin mining chips into everyday devices like USB battery chargers, routers, printers, gaming consoles, set-top boxes and -- the piece de resistance -- chipsets to be used by internet of things devices.

21 Inc wants to put your toaster to work, forging our cryptocurrency future."

Here: http://ftalphaville.ft.com/2015/04/30/2127543/meet-the-company-that-wants-to-put-a-bitcoin-miner-in-your-toaster/ although the link will not last long.