For hobbyists trying to strike it rich with cryptocurrency mining, but who don’t have access to gigantic warehouses where they can park the hardware, making money means packing a bunch of very loud and very hot computers into your house or apartment.
Some at-home cryptocurrency miners are harnessing the heat that powerful mining equipment—called ASICs—give off. Motherboard’s Daniel Oberhaus used mining equipment (albeit graphics cards, not ASICs) to stay warm during a storm once, and a Redditor posting under the handle “gta3uzi” just took it to another level. In a Tuesday post by gta3uzi on the /r/Bitcoin subreddit, they revealed a system for heating hot water using ASICs so you can make money while you chill in a steamy bath.
“Imagine a crypto heated swimming pool, or anything else you could heat with the output from a small, medium, or large-scale mining operation,” gta3uzi wrote on Reddit. Some of their suggestions for using the hot water include creating a sauna, heating a home, drying one’s hair, and even cooking a steak sous vide.
When I reached gta3uzi over Reddit, and then over Twitter, he told me that his name is “Lee” and he works in IT in Alabama. Lee used to mine cryptocurrency with graphics cards, he told me in a message, and when he recently rediscovered an old digital wallet containing the proceeds from that endeavour he decided to reinvest in some ASICs. “After realizing how much waste heat is generated by this equipment I decided to try and recycle it in a productive way,” he told me.
Lee’s system—which he set up briefly in January—is “extremely simple,” he told me, and makes use of a water-to-air intercooler like you’d find in a supercharged car. Ambient air is pulled into the system to cool the ASICs, and the heated air is pushed through an intercooler that has water constantly being pumped through it from a source, like a bathtub. The heat is transferred to the water, and voila—computer-heated water suitable for anything you’d normally use hot water for. In fact, Lee told me, it worked a little too well.
“It was a little too effective if I left it running all day as it produced baths of up to 122F/50C,” he wrote. “Dangerously hot, especially as I have a few pets who could fall in if they somehow gained access to the bathroom. I took the experiment down to preserve the safety of my living space. Safety is an absolute priority to me.”
Lee said that his mining operation made a 10 percent profit after electricity costs before he turned it into a water heater. But after the ASICs eliminated his $80 USD heating bill in addition to generating new cryptocurrency, Lee estimated that his mine’s profit went from 10 percent to 47 percent. So would he try it again?
“Absolutely,” Lee wrote. “It is huge fun and I am constantly exploring new applications for this method of heat recycling and ASIC thermal management. My only limitation is that I do not have the space or resources to scale it beyond the small prototypes you see in the photos I provided.”
This article originally appeared on Motherboard.