Hydro-cooled Bitcoin miners are now the most efficient machines on the market, and the price gap between the newest and the previous generation has never been wider. Here are eight hydro Bitcoin miners on sale today, compared on efficiency, price per terahash and what they net per day.
By Michal Beno, CEO, OneMiners18 October 2026
For lowest running cost, the Sealminer A4 Ultra Hyd (9.45 J/TH) and the Antminer S23 Hyd family (9.5 J/TH) are the most efficient Bitcoin miners on sale. For lowest price per terahash, the previous-generation Antminer S21+ Hyd 395T and S21e Hyd 338T cost about $5.6 to $6.3 per TH, a fraction of the S23 Hyd's $21.2. On a hosting rate of $0.048 per kWh, the cheaper S21-generation units pay back soonest at today's numbers; the newest units keep the widest margin if difficulty keeps rising.
9.45
J/TH, most efficient (A4 Ultra Hyd)
1.16 PH/s
single unit, Antminer S23 Hyd 3U
$5.6
lowest price per TH (S21e Hyd 338T)
$0.173
break-even per kWh at 9.5 J/TH
OneMiners catalogue, 14 October 2026; revenue from mempool.space and CoinGecko, 14 October 2026.
KEY TAKEAWAYS
What is a hydro Bitcoin miner?
A hydro (or "Hyd") Bitcoin miner has no fans blowing air over the chips. Instead, coolant flows through plates attached to the hash boards and carries the heat to a dry cooler or heat exchanger outside. Water moves heat far better than air, so the chips can run at a steady temperature, the machine is almost silent, and more hashrate fits in one box. The trade-off is infrastructure: a hydro miner needs a coolant loop, pumps and plumbing. That is why most buyers place them at a hosting site that already has hydro racks.
8 hydro Bitcoin miners on sale, compared
Hydro Bitcoin miners at today's numbers
Antminer S23 Hyd 3U 1.16P
Antminer S23e Hyd 2U 865T
Antminer S21 XP+ Hyd 500T
Antminer S21e XP Hyd 430T
Antminer S21e Hyd 338TPrices: OneMiners catalogue, 14 October 2026. Net per day after power at $0.048 per kWh, revenue $0.0395 per TH per day (difficulty 132.72T, BTC $83,399), before pool fees. Payback = price / net per day, at today's numbers; not a forecast.
Efficiency: joules per terahash
Lower is better
Efficiency from the OneMiners catalogue (power and hashrate as listed). Gold = under 10 J/TH.
The newest generation: S23 Hyd, S23e Hyd and Sealminer A4 Ultra
The Antminer S23 Hyd 580T is the reference hydro miner of 2026: 580 TH/s for 5,510 W, or 9.5 J/TH. The S23 Hyd 3U doubles that to 1.16 PH/s for 11,020 W in a single rack-mount unit, and the S23e Hyd 2U sits between them at 865 TH/s and 10 J/TH. The Sealminer A4 Ultra Hyd from Bitdeer matches them on efficiency (9.45 J/TH, 886 TH/s) at a notably lower price per TH, about $11.3 against $21.2 for the S23 Hyd 580T. At $0.048 per kWh the A4 Ultra nets about $25 a day and the S23 Hyd 3U about $33, at today's numbers. For a deeper look at the Bitmain unit, read the Antminer S23 Hydro review.
The value generation: S21 XP+ Hyd, S21e XP Hyd, S21+ Hyd and S21e Hyd
The previous generation runs at 11 to 17 J/TH, but it costs much less per terahash. The S21e XP Hyd 430T (13 J/TH) is a middle ground at about $8.1 per TH. The S21+ Hyd 395T and S21e Hyd 338T are the cheapest ways into hydro mining, at about $6.3 and $5.6 per TH. Their break-even power prices (about $0.110 and $0.097 per kWh) are still more than twice a hosting rate of $0.048, so they keep a healthy margin today.
Price per terahash
US dollars per TH/s, OneMiners catalogue
Prices 14 October 2026. Gold = under 6 dollars per TH.
Simple payback at today's numbers
Months, at 4.8 cents per kWh before pool fees
Payback = price / net per day at today's difficulty and Bitcoin price. Difficulty usually rises over time, which stretches payback; a higher Bitcoin price shortens it. Not a forecast.
Which hydro miner fits which buyer?
Quick picks
Based on the comparison above. Your own power price changes the answer: the more expensive your power, the more efficiency is worth.
Sealminer A4 Ultra Hyd 886T$9,999Hashrate886 TH/sEfficiency9.45 J/THPower draw8,372 WBreak-even power$0.174/kWhNet/day at 4.80c$25.36View on OneMiners
Antminer S23 Hyd 580T$12,299Hashrate580 TH/sEfficiency9.50 J/THPower draw5,510 WBreak-even power$0.173/kWhNet/day at 4.80c$16.56View on OneMiners
Antminer S21+ Hyd 395T$2,499Hashrate395 TH/sEfficiency15.00 J/THPower draw5,925 WBreak-even power$0.110/kWhNet/day at 4.80c$8.78View on OneMiners
From the OneMiners catalogue, prices 14 October 2026. Net per day at $0.048 per kWh, at today's numbers, before pool fees.
Hydro miners are the most efficient Bitcoin miners you can buy, and efficiency is what protects a miner when difficulty rises, as it did again this week. The right choice depends on budget: the S23 Hyd and A4 Ultra for the longest life, the S21 hydro units for the lowest entry price. Either way they need hydro-ready racks, which OneMiners provides at its hosting sites, from $0.048 per kWh and from $0.0364 per kWh on a 7-year prepaid contract. Buyers who prefer to spread the cost can use Buy Now, Pay Later.
Frequently asked questions
What does Hyd mean on a Bitcoin miner?
Hyd means hydro cooling: the miner is cooled by liquid instead of fans. It has nothing to do with hydroelectric power.
What is the most efficient Bitcoin miner in 2026?
Among machines on sale, the Sealminer A4 Ultra Hyd (9.45 J/TH) and the Antminer S23 Hyd family (9.5 J/TH).
Can I run a hydro miner at home?
It is possible but hard: you need a coolant loop, pumps, a dry cooler and high-power wiring. Most owners host hydro miners at a site with hydro racks.
Is the Antminer S23 Hyd worth it?
It has the lowest running cost per TH and the highest break-even power price, so it holds up best as difficulty rises. It also costs the most per TH, so payback at today's numbers is longer than cheaper units.
Which hydro miner pays back soonest?
At today's numbers and 4.8 cents per kWh, the cheaper S21-generation hydro units, because their price per TH is a fraction of the newest models.
Hydro miners need hydro racks. Buy the miner and host it in one step.
Browse Bitcoin minersSee hosting locationsSOURCES AND DATA
- Miner prices, hashrate and power: OneMiners catalogue, 14 October 2026
- Bitcoin difficulty 132.72T and hashrate: mempool.space, 14 October 2026; Bitcoin price: CoinGecko, 14 October 2026
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, news reports and the OneMiners catalogue as of 14 October 2026 and can change quickly. Net-per-day figures are at today's numbers, before pool fees, and are not a forecast. Crypto prices can fall as well as rise. No return is offered or implied. Do your own research.
