Heat Reuse
Heating with miners
Depending on the model, a hydro miner draws 4-11 kW and releases almost all of it as heat into a water loop. Connect it to a buffer tank or heating loop and the mining revenue covers part of your heating bill. Whether that pays off depends mostly on what you pay for electricity. Further down we do the math, including the cases where a heat pump is cheaper.
~100%
of the power becomes heat
up to 80 °C
water at the outlet, depending on model
24/7
continuous heat
How the heat gets used
The miner replaces the immersion heater, not your heating system. Radiators, buffer tank and pipes stay as they are. The miner's own loop stays closed, and a plate heat exchanger hands the heat to your buffer tank. Everything after that is ordinary heating equipment.
Hydro ASIC
4-11 kW of heat
Plate heat exchanger
Miner loop ⇄ house loop
Buffer tank
300-1,000 L
Radiators & hot water
Floor heating · shower · pool
How hot the water gets depends on the model. MicroBT rates the Whatsminer M64 Hydro at up to 80 °C at the outlet and the M63S+ Hydro at up to 70 °C. Bitmain specifies the permitted inlet temperature for its hydro units (up to 40-50 °C), and the outlet runs a few degrees above that. Hot water leaves the miner on the supply side and comes back cooler on the return to the hashboards.
The physics
Physically, an ASIC miner is an electric resistance heater that does some computing on the side. Almost all of the power it draws becomes heat; sound and radiation account for fractions of a percent. An air-cooled Antminer S21 (151 TH bin) blows its roughly 2.6 kW into the room as warm air, and a hydro unit passes the same power into your loop as warm water. The hydro units in our shop range from about 4 to 11 kW. You can control the heat output: Whatsminer units can be tuned by about ±20% in firmware, Bitmain units further and in finer steps, automatically through Home Assistant if you like.
~100% power → heat · continuous · water up to 80 °C
2.6kW
S21 Air (151 TH)
5.9kW
S21+ Hyd (395 TH)
8.7kW
S23e U2H
Heat output per unit, from the unit data in our shop
When it pays off and when it doesn't
At German household electricity prices ($0.30-$0.40/kWh) and mining revenue of roughly $0.10-$0.15 per kWh, depending on bitcoin price and difficulty, a heat pump is cheaper per kilowatt-hour of heat in most cases. It turns one kilowatt-hour of electricity into about three kilowatt-hours of heat; a miner turns it into one. Against a plain electric heater the miner always wins, because it delivers the same heat and earns bitcoin on top. For a look at such a device in daily use, see heise's test of a mining space heater.
It pays off when your electricity costs less than the market price (PV surplus, industrial tariff, direct marketing), when you need the heat anyway, or when you can feed a heat network at container or industrial scale.
Heat pump
Cheaper per kilowatt-hour of heat in most cases on household electricity without solar. We won't tell you otherwise.
Electric heater
A plain electric heater loses to mining heat: the same heat output, but no bitcoin revenue.
Below-market power
PV surplus, industrial tariff, direct marketing, or heat you would buy anyway. This is where mining heat clearly wins.
Mining on solar surplus
Home Assistant can tie a miner into your energy management, for example with the open-source integration hass-miner. It shows the miner's status, switches it on and off and, with suitable firmware such as Braiins OS or VNish, sets a power limit. An automation reads your PV surplus and adjusts the miner to match: with plenty of solar power it runs at full power, and as the surplus drops it is throttled or stopped. That way the miner heats with your own solar power instead of expensive grid power.
The same works for businesses. A swimming pool, hotel or plant with its own PV system can turn surplus that would otherwise be sold cheaply or curtailed into heat for pools, showers or halls, and take load off the gas boiler or heat pump.
Air or water
Which one fits depends on where the heat needs to go.
Air for workshops, garages and halls
Air-cooled units like the Antminer S21 blow out warm exhaust air (around 30-60 °C). That suits any place that needs a lot of heat and doesn't mind noise: as site heating on a construction site, to keep a greenhouse frost-free, or for drying wood, hay or paint booths. An S21 runs at about 75 dB and gets quieter when throttled.
Hydro for heating loops and hot water
Hydro miners release their heat into a closed water loop, at up to 80 °C depending on the model. Through a heat exchanger you connect them to a buffer tank, floor heating or hot water system. They are much quieter than air-cooled units, quiet enough for living spaces.
Where the heat can be used
From a single-family house to a heat network, split into private and commercial use.
Private
Hot water & heating loop
A hydro miner in your heating loop needs a plate heat exchanger and a buffer tank. A 4 kW unit running around the clock produces about 35 MWh of heat a year. That is more than a typical unrenovated older house needs for heating (about 20-30 MWh) and several times what a new build needs (about 5-7 MWh). It covers hot water for a household of four (about 2,500-3,500 kWh a year) all year round; for the rest you throttle it or run it only in winter.
See hydro units in the shopWorkshop, garage & pool
Where noise is fine, an air-cooled unit (about 75 dB) heats a workshop, garage or storeroom with warm exhaust air. If the heat should go quietly into water, for a pool, hot tub or sauna preheating, use a hydro unit with a heat exchanger. The heat is produced either way; this way you use it instead of venting it.
Commercial
Hotel, spa & swimming pool
Businesses often have the steady heat demand that keeps a miner busy all year. An indoor pool needs roughly 0.15-0.2 kW per m² of water surface during opening hours, so about 50-60 kW for a 25 m pool. Sport pools are kept at 26-28 °C, leisure and therapy pools at up to 35 °C; both are within what hydro miners deliver. One example is the Bathhouse in Brooklyn, which heats its pools and showers with waste heat from miners (MIT Technology Review, 2025).
Greenhouse & aquaculture
Plants and fish need steady low-temperature heat, which suits mining waste heat. Since January 2026 Canaan and Bitforest Investment have been testing a 3 MW setup in Manitoba where liquid-cooled miners preheat water for a tomato greenhouse to above 75 °C; Canaan estimates that about 90% of the power is used as heat. In 2018 the Myera Group in Manitoba heated a small greenhouse with waste heat from about 30 miners, fertilized with water from tanks holding about 800 Arctic char. In the energy-crisis winter of 2022, miners run by Bitcoin Brabant helped heat a tulip greenhouse near Amsterdam.
Industry & process heat
In workshops and halls, air-cooled units or hydro units of up to about 9 kW each (400 V, CEE 16 A) can replace the space heating; noise doesn't matter there. Waste heat can also drive processes: KryptoVault dried firewood with the warm exhaust air of its miners in Hønefoss, Norway; Sazmining dries fish in a Norwegian fishing village north of the Arctic Circle; and Softwarm in Idaho heats a car wash and the water tank of a concrete plant.
District heating & neighborhoods
At container and megawatt scale, mining heat can supply whole networks. Since 2024 MARA has been heating a network for about 11,000 residents in the Satakunta region of Finland. Since October 2024 Terahash Energy has been feeding about 70 °C water from 1 MW of miners straight into the district heating network of a Finnish town of about 12,000 people.
Hydro units in the shop
These units release their heat into a water loop straight from the factory. You need no modifications and no retrofit kit.
4 hydro units
Browse all minersAntminer S23e U2H
Hashrate
865 TH/s
Efficiency
10 J/TH
$/TH
$12.9
Cooling
Liquid
Price
$11,141Avalon A1566 HA
Hashrate
460 TH/s
Efficiency
17.8 J/TH
$/TH
$7.82
Cooling
Liquid
From
$3,597Avalon A1566E HA
Hashrate
424 TH/s
Efficiency
17.8 J/TH
$/TH
$4.83
Cooling
Liquid
Price
$2,048Antminer S23 XP Hyd
Hashrate
600 TH/s
Efficiency
8.9 J/TH
$/TH
$28.5
Cooling
Liquid
Price
$17,112Run the numbers yourself
Your miner, your electricity price, your PV surplus: what a mining heater brings in each month, what it costs in power and what the heat is worth. Calculated with current network data. These are estimates, not promises.
Miner
Power & solar
Share of grid power
0%
Runtime per day
16h
Your own solar power isn't free either: every kWh the miner uses is a kWh you could have fed into the grid and been paid for. That is why this uses the feed-in tariff instead of the grid price.
Heat
Bitcoin network
Current network data
Result per month
$443
Mining revenue
$310
value of the heat
$0
Power cost (grid)
$103
feed-in tariff forgone
$650
Result
- sats earned per day
- 17,662
- blended power price / kWh
- $0.04
- your heat costs / kWh
- -$0.17
- heating replaced / kWh
- $0.12
The mining revenue exceeds your power cost: you are effectively paid $0.17 for every kWh of heat.
Estimated with the current bitcoin price, difficulty and fee level; all three move. Before pool fees, without the cost of hardware and installation. No guarantee of returns.
Plan the loop before you buy the miner.
Send us your heat demand, your electricity price and what heating you already have. We will work out with you which units and components are worth it.