Antminer S21 Hydro

335 TH/s at 5,360 watts. 16.0 J/TH, which is rank 43 of 85 in this comparison.

What this machine earns at your electricity price

Electricity price

cents per kWh

Net per day

–

Break-even price

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Payback

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Further assumptions

Bitcoin price in euro

Pool fee in percent

Purchase price in euro

Waste heat replaces heating A miner in a living space heats it. Whatever gas or electricity you therefore do not buy counts against the power bill, but only in the months you would be heating anyway.

Network hashrate 973 EH/s ·

Household prices per Eurostat, 2. Halbjahr 2025, including all taxes and levies. Your own tariff may differ considerably; cheap switching offers often sit ten cents below. Just type yours in.

The break-even electricity price is the price per kilowatt-hour at which earnings exactly cover the power bill. Below it the machine earns, above it the machine burns money. In central Europe that is the number almost everything turns on.

The sum behind it

Earned per day–

Earned per day in euro–

Power used per day–

Power cost per day–

of which heat credit–

BTC per day = hashrate ÷ network hashrate × 144 blocks × 3.125 BTC × (1 − pool fee) Power cost = watts ÷ 1000 × 24 h × price per kWh Break-even = earnings in euro ÷ kilowatt-hours per day

Not included: connection, cooling, power-supply losses, downtime and maintenance. Water cooling adds the loop itself, hosting adds the slot fee. Network difficulty rises over the long run, which lowers earnings at the same hashrate; the payback figure uses today's values and is therefore on the optimistic side.

Specifications

ManufacturerBitmain

Hashrate335 TH/s

Power draw5,360 W

Efficiency16.0 J/TH

CoolingWater

Form factorStandalone unit

AlgorithmSHA-256

Price per terahash21 €

Market reference6,885 € / 7,900 $

Assessment

The S21 Hydro needs a water loop, which means a heat exchanger, pumps and somewhere for the waste heat to go. In return you get 16 J/TH and a machine packed far more densely than any air version. For a single unit at home the effort is rarely justified; for a row of machines in a hall it is exactly the right approach. Compare it with the S21 XP+ Hyd, which is considerably more efficient for the same kind of installation.

Against machines of similar efficiency

Model	TH/s	J/TH	Net/day	Break-even	Price
WhatsMiner M60S++	220	15.5	–	–	—
NerdQaxe++	4.8	15.6	–	–	—
Antminer S21 Imm	215	16.0	–	–	—
Antminer S21 Hydro	335	16.0	–	–	6,885 €
WhatsMiner M79S	1,350	16.5	–	–	12,688 €
Antminer S21+	216	16.5	–	–	3,746 €
SealMiner A2	226	16.5	–	–	4,261 €

All 85 models compared

Do the sums before you buy

If you do not like the numbers, you are not alone: at household prices almost none of these machines pay off in central Europe. If you still want to understand how mining works economically, you can play it through in the Coinovo app, with the same models and the same formulas, but without hardware and without a power bill.

Open Coinovo