Photo: Mirko Tobias Schaefer / Wikimedia Commons, CC BY 2.0
Thirty homes and buildings in Finland and the Netherlands are now heated by bitcoin mining machines that earn cryptocurrency while they run, and their Finnish maker says the mining income can cover the entire power bill as long as bitcoin stays above roughly $70,000.
The company, SunBit, delivered its first production “Bitcoin Boilers” in 2025 and now has 30 systems operating, founder and CEO Elmeri Suomi said in an interview published Sunday. Twenty-nine are in Finland, where they have replaced or cut back on gas, oil, wood and district heating, and one unit in the Netherlands replaced gas heating at a commercial property.
How it works
Every kilowatt-hour a mining computer draws comes out as heat. SunBit’s system captures that heat in water at up to 60 degrees Celsius and pushes it through a building’s radiators and floor pipes the way an oil or gas boiler would, while the machine mines bitcoin the whole time it runs. Heat the house cannot use, most of it in summer, is dumped outside through a dry cooler.
The homeowner buys the equipment, pays for the electricity and keeps the bitcoin. Under SunBit’s model, with bitcoin at about $82,000, network computing power at 1,040 exahashes per second and power at about 11 cents per kilowatt-hour, one machine earns slightly more than its roughly $5,200 annual power bill, making the heat effectively a free by-product of mining. Bitcoin traded near $81,500 as of U.S. morning hours Friday, and SunBit puts the break-even for covering the power bill at just under $70,000, a figure that does not include the cost of the system itself.
Not exactly free
The equipment is a real outlay. SunBit’s own pricing lists the heating system at 14,500 to 22,300 euros plus VAT depending on the property and equipment choices, with the mining hardware priced on order, about $20,000 or more all told according to the report. Suomi puts the payback period at three to six years through mining income.
That timeline runs into a built-in deadline: bitcoin’s next “halving,” expected in spring 2028, will cut the new coins awarded to miners from 3.125 to 1.5625 per block. SunBit’s payback calculator does not factor in the halving because the company declines to predict prices or network difficulty, Suomi said, adding that it explains the event to every customer. Holding the company’s own assumptions fixed, a miner-heated home would keep its free heat after the halving only if bitcoin trades above roughly $131,000.
Oil is easy to beat, heat pumps are not
Against heating oil, the math can work: replacing a typical 2,300-liter-a-year oil habit could eliminate a roughly $5,000 fuel bill. A heat pump is a tougher rival, delivering 2.5 to 3 kilowatt-hours of heat per kilowatt-hour of electricity while a miner delivers exactly one. The miner’s edge comes only from mining revenue, which rises and falls with bitcoin’s price and mining competition. Suomi argues winter is where a miner pulls ahead, since its output does not drop in extreme cold the way an air-source heat pump’s efficiency does.
JBizNews Desk | Helsinki
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