CoinDesk
A 180-square-meter house in Nokia, Finland, has disconnected from the district heating network and now heats its rooms with a bitcoin miner. The machine is one of 30 systems running from Finnish startup SunBit, which sells the setup as a Bitcoin Boiler: every kilowatt-hour the miner draws comes out as heat, captured in water at up to 60°C and pushed through radiators and floor pipes like an oil or gas boiler. With bitcoin trading near $81,500, each machine earns slightly more than the electricity it burns, so the heat becomes a free by-product. SunBit puts the owner's break-even at just under $70,000, roughly 15% below Friday's price.
Why it matters
Finland is already the testbed for heating with mining. MARA's systems feed waste heat into district heating networks in Satakunta and Seinäjoki, warming about 80,000 residents. SunBit pushes the model to the consumer: the property owner buys the machine for roughly $20,400 to $31,400 installed, pays the power bill and keeps the bitcoin. Under SunBit's assumptions (bitcoin at about $82,000, network hashrate at 1,040 exahashes), a 495-terahash Antminer S21 XP Hydro mines about one-twelfth of a bitcoin a year, worth roughly $6,100 after SunBit's optional 10% service fee, against about $5,200 in annual power at 11 cents per kilowatt-hour.
Market impact
The pitch works against oil but not against heat pumps, which deliver 2.5 to 3 kilowatt-hours of heat per kilowatt-hour of electricity versus the miner's one. Payback runs three to six years, and bitcoin's spring 2028 halving lands before most owners recoup the system cost. Holding SunBit's inputs fixed, halving drops mining income from about 13 cents to 7 cents per kilowatt-hour, below the 11-cent power price. Free heat after 2028 requires bitcoin above roughly $131,000, about 60% above Friday's level, meaning early buyers get roughly 18 months at today's margins before the cut.
Frequently asked questions
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How does a Bitcoin Boiler heat a house?
Every kilowatt-hour a mining computer draws comes out as heat. SunBit captures that heat in water at up to 60°C and pushes it through radiators and floor pipes the way an oil or gas boiler would, while the machine mines bitcoin.
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At what bitcoin price does the heat stop being free?
SunBit puts the owner's break-even at just under $70,000, roughly 15% below bitcoin's Friday price near $81,500. Below that level, mining income after fees no longer covers the electricity bill.
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What does a SunBit Bitcoin Boiler cost to install?
Installed systems cost roughly $20,400 to $31,400. SunBit models payback at three to six years, though the calculation leaves out bitcoin's expected spring 2028 halving.
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How does the 2028 halving affect the economics?
The halving cuts block rewards from 3.125 to 1.5625 bitcoin, dropping mining income from about 13 to 7 cents per kilowatt-hour, below the 11-cent power price. Free heat after the halving requires bitcoin above roughly $131,000.
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Is mining heat more efficient than a heat pump?
No. A heat pump delivers 2.5 to 3 kilowatt-hours of heat per kilowatt-hour of electricity, while a miner turns each kilowatt-hour into exactly one. The miner's advantage is revenue from mining, not heating efficiency.
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