Pencil drawing of the 21energy Bitcoin Central Heating

Water heater Floor standing Announced

21energy Bitcoin Central Heating

An announced whole-house heating system from Austria's 21energy. A water-cooled bitcoin miner takes the place of an oil or gas burner and heats a storage tank that feeds radiators, underfloor heating and hot water. 21energy quotes about 7 kW of heat (7 to 10 kW in its headline) and water at 70 °C or more. There is no price or pre-order yet, only a waitlist. The maker says it launches in Q4 2026, and it announced a field test with Tyrolean households from June 2026, with no results published so far.

We haven't found a store price yet.

Reviews from Nostr ↓

Hashrate—
Power (stock)7,000 W lowest 11 Whighest 22 kW 45th highest of 199 (the bar uses a log scale)
Efficiency—
Earns per kWh—
Heat output23,885 BTU/h worst 38 BTU/hbest 75,067 BTU/h 45th best of 199 (the bar uses a log scale)
Noise—
Price per TH—

Where to buy

No store listings yet. Know where to buy it? Tell us.

Heat, running cost and sats

Heat per day
—
Electricity per day
—
Mining earns per day*
—
Net cost per day
—
Net cost per kWh of heat
—
Solo: chance of a block per year
—
Earns per kWh, on 3-month averages
—
Payback
—

*What a pool would pay on average at today's difficulty, block reward and bitcoin price, before pool fees. Solo miners usually earn nothing, and very rarely a whole block. A plain electric heater turns the same electricity into the same heat, so the mining income is what makes the difference.

Payback is how long the bitcoin a device earns takes to add up to its price. It leaves out electricity, which buys the heat: compare earnings per kWh with your electricity price to see whether mining alone covers it. It uses the average of the last 3 months, to 12 Nov 2026: bitcoin at $79,558, 969 EH/s on the network and 3.15 BTC a block, less a 2% pool fee, for the hours you set. It cuts the block subsidy in half at each halving, the next around Apr 2028, and otherwise assumes those carry on unchanged, which they won't. Income at today's difficulty and price is about 17% below that average. Hashrate usually rises, though miners that stop paying after a halving may switch off, which leaves more for the rest. How we work it out.

Specifications

Brand21energy
ModelBitcoin Central Heating
SKU—
TypeWater heater · Home
Form factorFloor standing
CoolingWater (hydro)
Production statusAnnounced
Launch date—
Hashrate—
Power consumption (stock)7,000 W *
Mining efficiency—
ASIC chipNot known yet
Heat output23,885 BTU/h
Input voltage—
Frequency—
Net dimensions (W × D × H)—
Net weight—
Noise—
Operating temperature—
Hot waterAbout 151 L (40 US gal) an hour, from 10 to 50 °C (our estimate)
Colours—
Company based inAustria
Made inAustria

* Not confirmed by the maker's own documents yet.

Features

  • Water-cooled (hydro) ASIC miner, no fans
  • Connects to a standard storage (buffer) tank; can be fitted to an existing tank
  • Works with radiators and underfloor heating
  • Central heating and domestic hot water from one system, no separate boiler
  • Water heated to 70 °C or more
  • Main heat source, or an add-on alongside a heat pump, gas or oil boiler
  • App control: heats when power is cheapest, using solar surplus and dynamic tariffs
  • Mined bitcoin paid out daily ('Bitcoin Cashback')
  • Developed and made in Austria

Reviews

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Sources and data notes

Not yet confirmed from the maker's own documents: power (heat output, not a stated electrical draw: 'around 7 kW' in the FAQ and page text, '7 to 10 kW' in the headline, 10 kW in a May 2026 blog post); hashrate (no miner model or hashrate published); efficiency (not published); launch date (maker says Q4 2026, FineEngineering says November 2026; not on sale on 2026-11-05); model (no model name; the maker calls it Bitcoin Central Heating); SKU; summary (Tyrol field test announced for June 2026; no start or results published); images (concept render from a blog post, not a product photo); dimensions; weight; noise (maker says whisper-quiet, no figure); input voltage; frequency; operating temperature; area heated (only 'for single-family homes').

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