Bitcoin Mining Heat Reuse: Greenhouses, Homes and District Heating

A Bitcoin miner is, physically, an electric heater that also secures the Bitcoin network. Here is how that heat is already warming towns, greenhouses and pools, and where the idea runs out.

By Michal Beno, CEO, OneMiners28 October 2026

A Bitcoin miner is a box of specialised chips called ASICs (application-specific integrated circuits) that do one job: computing SHA-256 hashes, trillions of guesses per second, in the race to find the next block. Doing that work moves electrons through billions of tiny transistors, and the energy has nowhere to go but heat. A miner does not store energy, lift anything or emit light worth mentioning. So, by the law of conservation of energy, the electricity that goes in comes out as heat, through the fans as warm air or through the coolant as warm water.

That is exactly what an electric space heater does, with one difference: the heater only makes heat, while the Bitcoin miner makes the same heat and also does useful work for the Bitcoin network, earning Bitcoin in the process. That is why heat reuse appeals to engineers. If you need the heat anyway, the mining comes almost free.

A BTU (British thermal unit) is the heat needed to warm one pound of water by one degree Fahrenheit; heaters and air conditioners are often rated in BTU per hour. A common portable electric heater draws about 1,500 W, or about 5,118 BTU/h. One S21 Pro therefore heats like about 2.5 of those heaters running flat out, all day, every day.

From watts to heat: popular Bitcoin miners

Bitcoin miner	Power	Heat per hour	Heat per day
Avalon Nano 3S 6T	140 W	478 BTU	3.4 kWh
Antminer S21 Pro 245T	3,675 W	12,539 BTU	88.2 kWh
Antminer S23 Hyd 580T	5,510 W	18,800 BTU	132.2 kWh
Antminer S21+ Hyd 395T	5,925 W	20,216 BTU	142.2 kWh

OneMiners calculation from rated power, OneMiners catalogue, 6 October 2026. Real draw varies a few percent with firmware and temperature.

Heat reuse is not just a whiteboard idea. These projects have been reported by the companies involved or by major news outlets.

District heating in Finland

District heating means one central plant heats water and pumps it through insulated underground pipes to many buildings. It is common in Nordic countries. MARA launched a pilot in the Satakunta region of Finland in June 2024. In a July 2025 update, MARA said the Satakunta site supplies about 3.5 MW of heat at 55 to 78 C, and a second site in Seinajoki provides about 1 MW from miners plus 0.25 MW from heat pumps at 50 to 60 C. MARA says both were connected to existing networks in under 30 days and that, in Seinajoki, the heat replaced peat, oil and wood.

City heating in North Vancouver

In March 2022, North Vancouver's city-owned utility, Lonsdale Energy Corporation, partnered with MintGreen to add Bitcoin mining heat to its hydronic district energy system, which serves about 100 residential and commercial buildings. MintGreen said its "Digital Boilers" recover more than 96% of the electricity used as usable heat, running mainly on BC Hydro's hydropower.

Greenhouses, pools and drying

In December 2022, AFP reported on a Dutch tulip grower whose greenhouse was heated by six Bitcoin miners run by a firm called Bitcoin Brabant, powered partly by rooftop solar, as gas prices soared. In Brooklyn, the Bathhouse spa submerges miners in a cooling fluid and uses a heat exchanger to warm its pools, as Fortune reported in December 2023. In Norway, Kryptovault used warm exhaust air from its hydro-powered site in Honefoss to dry timber logs, Cointelegraph reported in February 2022.

How useful heat is depends on its temperature, not just its amount. Engineers call warm air or lukewarm water low-grade heat: there is a lot of it, but it is hard to move and too cool for many jobs. An air-cooled miner blows out warm air, fine for a garage or a drying room but hard to pipe across a town.

A hydro-cooled (water-cooled) Bitcoin miner pumps liquid through cold plates on the chips. Bitmain's specification for the Antminer S21 Hyd allows coolant to enter at 20 to 50 C at 8 to 10 litres a minute. At its rated 5,360 W and 8 litres a minute, the water warms by about 10 C on the way through, so a miner fed at 50 C returns water near 60 C. That is hot enough for many heating systems.

Start with the miner. At today's numbers, an Antminer S21 Pro (245 TH/s) earns about $9.75 a day in Bitcoin before pool fees, at a hashprice of $0.0398 per TH per day. Its power at $0.048 per kWh costs about $4.23 a day. Now suppose the owner sells or uses the 88.2 kWh of heat. Every kWh that replaces a gas boiler or an electric heater is value on top of the mining revenue.

That last bar is the honest limit. A miner beats a plain electric heater easily, because it makes the same heat and earns Bitcoin too. But a heat pump moves heat from outside air or the ground and delivers several units of heat per unit of electricity, so in pure heating terms it wins. Heat reuse works best where a building or network needs a steady base of warm water and a miner is already running there.

Large mining sites face the mirror image of the heating problem: they must get rid of heat cheaply. That is one reason miners cluster in cold places with cheap hydropower, such as the Nordics and Canada. Cold air does a lot of the cooling for free, which lowers the energy spent on fans and chillers and helps machines run steadily. In most of these sites, the heat is simply released to the air, because there is no town next door to buy it.

OneMiners hosting locations include Norway (100% hydro) and Canada (hydro), alongside warm-climate sites such as Ethiopia, where evaporative cooling walls handle the heat. For a hosted miner, the practical benefits of a cool, hydro-powered site are stable temperatures, clean power and a low electricity rate. Hosting starts from $0.048 per kWh, and from $0.0364 on a 7-year prepaid contract, and hosted miners carry a 7-year warranty that covers defects, not normal wear.

Antminer S21 Pro 245T$2,299Hashrate245 TH/sEfficiency15.00 J/THPower draw3,675 WBreak-even power$0.111/kWhNet/day at 4.80c$5.52View on OneMiners

Antminer S21+ Hyd 395T$2,499Hashrate395 TH/sEfficiency15.00 J/THPower draw5,925 WBreak-even power$0.111/kWhNet/day at 4.80c$8.90View on OneMiners

Antminer S23 Hyd 580T$12,299Hashrate580 TH/sEfficiency9.50 J/THPower draw5,510 WBreak-even power$0.175/kWhNet/day at 4.80c$16.74View on OneMiners

Bitcoin miners from the OneMiners catalogue: one air-cooled, two hydro-cooled. Live prices 6 October 2026; net per day at $0.048 per kWh, at today's numbers, before pool fees.

Frequently asked questions

Michal Beno

CEO of OneMiners, the global Bitcoin mining hosting and hardware platform with 15 published hosting locations, 7-year fixed electricity contracts and a 7-year hardware warranty. He writes about the economics of industrial Bitcoin mining.

Informational only, not financial advice. Figures are a snapshot from public market data and news reports as of 5 October 2026 and can change quickly. Crypto prices can fall as well as rise. No return is offered or implied. Do your own research.