Finnish startup SunBit is using Bitcoin mining equipment to heat homes, with 30 systems operating at the time of a report published on November 9, 2026. The proposition is straightforward: capture miners’ waste heat and use their Bitcoin earnings to offset electricity bills. Whether that also repays equipment costing more than $20,000 is considerably less certain.
The report, attributed to CoinDesk’s Shaurya Malwa and translated by Chopper of Foresight News, describes a business model exposed to electricity prices, mining competition and Bitcoin’s next block-subsidy halving, expected in spring 2028. Its calculations are historical scenarios, not current market quotes or guaranteed returns.
How the heating system works
In Nokia, Finland, a 180-square-meter home disconnected from district heating and switched entirely to a SunBit “Bitcoin boiler.” The equipment converts almost all the electricity it consumes into heat, warming water to as much as 60°C for radiators and underfloor heating.
SunBit CEO Elmeri Suomi told CoinDesk that the company delivered its first production units in 2025. All but one of the 30 operating systems were in Finland; its first overseas installation, in Leersum in the Netherlands, also took place in 2025.
Other installations illustrate different uses: a 200-square-meter home in Kotka combined a miner with an existing oil boiler, while an old manor in Tampere used mining equipment instead of firewood to keep a 1,500-liter tank between 50°C and 60°C. A 3,000-square-meter industrial building in Vimpeli paired the system with an air-source heat pump and surplus electricity from a 30-kilowatt solar array.
Customers own the equipment, pay its electricity bills and retain the Bitcoin it produces, subject to any service and pool fees. Because miners are noisy, they are generally installed in basements or separate sound-insulated rooms.
The operating surplus depends on the assumptions
SunBit’s example used a Bitmain Antminer S21 XP Hydro running Braiins OS, with 495 TH/s of computing power and electricity consumption of approximately 5.3 kilowatts. Continuous operation would consume about 46,400 kilowatt-hours annually.
The model assumed:
- Electricity at $0.11 per kilowatt-hour, for an annual bill of roughly $5,200.
- Bitcoin at $82,000 and total network computing power of 1,040 EH/s.
- Annual production of approximately one-twelfth of a bitcoin.
- An optional SunBit service fee of 10%, leaving approximately $6,100 in Bitcoin revenue before a further 0.5% mining-pool fee.
On those assumptions, the report put the annual operating surplus at approximately $900. Without SunBit’s optional service, the modeled Bitcoin production was worth about $6,800 before the pool fee. The service includes round-the-clock remote monitoring, optimization around Finnish variable electricity prices and a mobile app; grid-balancing functionality was planned.
With Bitcoin trading around $81,500 at the time of the report, SunBit estimated an operating break-even price near $70,000 after its service fee. That threshold excluded the equipment purchase and assumed unchanged network computing power. More mining competition would reduce an individual machine’s output.
Actual customer evidence was limited. Suomi supplied a pool-dashboard screenshot showing that an early customer’s lower-powered, 358 TH/s S21+ Hydro had mined 0.039 BTC over the previous year, worth about $3,160 at the cited market price. That installation could replace roughly 2,000 liters of heating oil annually. SunBit could access early pilot customers’ data, but later customers used private pool accounts the company could not inspect.
Heat pumps remain the efficiency benchmark
The strongest comparison in SunBit’s example was against oil heating. A home consuming 2,300 liters annually at approximately $2.19 per liter would spend about $5,000 on fuel. Combining avoided oil costs with a modeled $920 annual mining surplus produced an estimated payback of about three and a half years on a roughly $20,200 installation, excluding additional equipment, maintenance and financing costs.
Elsewhere, the report cited installation prices of $20,400–$31,400 and estimated payback periods of three to six years.
But useful heat is not the same as total heat production. The report said the example home could not use more than half the miner’s output; an external dry cooler discharged excess heat outdoors, particularly in summer.
An air-source heat pump was the tougher competitor. The report used a heat-output ratio of 2.5–3 units per unit of electricity, versus approximately one for a miner. For a home requiring 25,000 kilowatt-hours of heat annually, SunBit estimated air-source heat-pump operating costs at around $1,100 and district heating at $3,170. Running a miner only long enough to meet that heating requirement produced a modeled $490 surplus after electricity costs.
The miner’s potential advantage therefore came from Bitcoin revenue, not superior heating efficiency. Suomi argued that its heat output remains stable in severe cold, unlike an air-source heat pump whose efficiency falls at temperatures around −25°C. Its financial performance, however, remains exposed to Bitcoin prices and mining difficulty.
The 2028 halving changes the calculation
The next halving is expected to reduce Bitcoin’s block subsidy from 3.125 BTC to 1.5625 BTC. Buyers installing systems in the winter discussed in the report could encounter that reduction before recovering their initial investment.
SunBit’s calculator did not incorporate the halving into its payback estimates. Suomi said the company explains historical halvings to customers but does not forecast Bitcoin prices or network computing power, or promise fixed returns.
Holding the report’s other assumptions constant, the halving would reduce mining revenue per kilowatt-hour from approximately $0.13 to $0.07—below the assumed $0.11 electricity cost. Net heating costs would then be around $0.04 per kilowatt-hour, close to the heat-pump running cost used in the comparison.
The report estimated roughly 18 months of the prevailing pre-halving economics for households installing that winter. Under its formula, Bitcoin would need to reach approximately $131,000 to preserve electricity-cost coverage after the halving. That figure was a conditional break-even calculation, not a price forecast, and it did not establish recovery of the upfront equipment cost.
The distinction is central: the equipment can continue supplying heat even when mining becomes less profitable. “Free heating” and investment payback depend on a much narrower set of financial conditions.
Original source: TechFlow’s published version of the CoinDesk report, published November 9, 2026, at 18:07:09 (UTC+8).