Hot-running computers as heating source

NICK EICHER, HOST: Next up on The World and Everything in It

Warming your house with your laptop?

It’s not as crazy as it sounds.

MARY REICHARD, HOST: No…When your laptop computer is working its hardest, it’s likely not going to stay on your lap for very long! Computer chips generate a whole lot of heat, and it’s wasted. For years it’s been necessary to use fans to cool them down.

EICHER: Recently we discussed the rise of cryptocurrency mining – where dedicated computers churn through complex math problems. The harder the computer works, the hotter it becomes.

One estimate found the electricity associated with a single Bitcoin transaction could power almost 30 houses for a whole day.

REICHARD: But some computer manufacturers are starting to put that formerly wasted energy to work: heating homes and buildings, while at the same time providing computing resources. WORLD Radio technology reporter Michael Cochrane is here now to explain.

So, Michael, I always knew that my computer put out a lot of heat—but 30 houses worth?

MICHAEL COCHRANE, REPORTER: Well, your laptop by itself wouldn’t be able to put out that much heat. But for the kind of computing power needed to perform cryptocurrency calculations, you typically use machines called “servers.” They have lots of high-speed chips to process those transactions. And they can get pretty hot! You’ve got to do something to cool them down or they’ll fry, so pumping that waste heat away to heat rooms is one way to deal with it.

REICHARD: Can you actually buy one of these “computer heaters?”

COCHRANE: Yes, earlier this month, a French startup started selling a wall-mounted home heater that features a computer optimized for mining the cryptocurrency Ethereum. It boasts two powerful Graphics Processing Units—or GPUs—that generate more than 450 Watts of heating power.

REICHARD: Wow, sounds like sci-fi becoming reality. What will one of these heaters cost me?

COCHRANE: The initial price isn’t cheap – it’s $3,600 – but here’s the cool thing (pardon the pun!): Since you are also mining Ethereum coins, your heater/computer is generating a positive cash flow that would pay you—at current rates—about $120 per month. The whole thing is controlled by a mobile app that receives the mined currency units and controls the computer.

REICHARD: So this heater could end up paying for itself in the long run?

COCHRANE: Absolutely! And you need to heat your house anyway – during the winter at least – so it would also offset the cost of the energy you’d otherwise use to do that.

REICHARD: Is the rise of cryptocurrency mining driving this new trend?

COCHRANE: Not so much driving it as kicking it into a higher gear. The original idea dates back to at least 20-11. Over the past five or so years, there have been efforts to place computer data centers in buildings so the heat they generate can be piped into the building. These centers are basically big rooms filled with racks of servers—the so-called “cloud.” But typically, to cool them, companies would have to use even more electricity in the form of air-conditioning units.

REICHARD: So, an entire home heating system could be replaced by a computer? Is that going to be possible one day?

COCHRANE: Yes! In 2011, a joint paper by Microsoft and University of Virginia researchers proposed replacing those big data centers with what they called “micro-datacenters.” These would be about the same size as a typical home furnace and put out the same amount of heat using the home’s existing infrastructure. Some of the computational power would be used by the homeowner and the rest would be sold back to the IT company managing the distributed data centers for cloud computing.

REICHARD: We’re all for saving dollars. So this whole approach could reduce costs by using the electricity for both heating and computing.

COCHRANE: Precisely. You’d be reusing both the power and the infrastructure that would normally be used for space heating alone. Plus, you’re using the homeowner’s house to contain the datacenter—and the internet connectivity is already there.

REICHARD: Well, all of this makes sense in theory, but will we ever see this concept take off?

COCHRANE: My prediction is that if cryptocurrencies really start to become mainstream, we will see more widespread use of these computer home-heating technologies. Here’s why: According to, the annual energy consumed in mining just one cryptocurrency – Bitcoin – is equivalent to about 10 percent of the energy usage of Canada, 17 percent of the United Kingdom’s energy usage, and more than 40 percent of Australia’s. And those figures are only going to grow. If we don’t find a way to leverage that energy usage into other, useful byproducts such as heating then it could put a huge strain on the power grid.

REICHARD: And to think in the 1980s I predicted computers would never take off!  Michael Cochrane reports on science and technology. Thanks, Michael.

COCHRANE: You’re welcome, Mary.

WORLD Radio transcripts are created on a rush deadline. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of WORLD Radio programming is the audio record.

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