Antminer S21 Hydro
Hydro-cooled S21 variant with 335 TH/s. Quieter than air-cooled models but requires water cooling infrastructure and 240V power.
Hydro-Cooled Miner
This miner uses a closed-loop liquid cooling system (hydro cooling) instead of traditional air cooling. Water or coolant circulates through internal channels to absorb heat from the ASIC chips, then transfers it to an external radiator or facility cooling loop.
Hydro-cooled miners run significantly quieter than air-cooled models since they eliminate or minimize fan noise. They also achieve higher hashrates and better efficiency because the chips can be driven harder while staying within safe thermal limits. The trade-off: hydro miners require compatible water infrastructure — inlet/outlet connections, a cooling distribution unit (CDU), and proper plumbing.
Hydro cooling is ideal for professional mining operations and data centers where water infrastructure already exists, or for home miners building a dedicated water-cooled setup to eliminate noise completely.
Professional-Grade Miner
This miner draws 5,360W and produces 50 dB of noise — it is designed for dedicated mining environments, not living spaces. Professional-grade miners deliver the highest hashrate and revenue per unit but require proper infrastructure: a 240V circuit, adequate ventilation or exhaust ducting, and a space where noise is not a concern (garage, basement, warehouse, or outdoor enclosure).
For home miners looking for a quieter alternative, consider our Bitcoin Space Heater builds or explore open-source miners like the Bitaxe that are purpose-built for residential environments.
Profitability Calculator
| Period | Revenue | Electricity Cost | Profit |
|---|---|---|---|
| Daily | $9.45 | $9.00 | $0.44 |
| Weekly | $66.12 | $63.03 | $3.09 |
| Monthly | $283.37 | $270.14 | $13.22 |
| Yearly | $3,447.64 | $3,286.75 | $160.89 |
Heating offset estimates the value of heat replacing an electric space heater during heating season (~6 months/year in Canada). Actual savings depend on your heating setup and climate.
Where to Buy the Antminer S21 Hydro
D-Central Technologies
CanadaBitcoin Mining Hackers since 2016. Ships from Laval, Quebec.
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United StatesWide selection of new and used ASIC miners. US-based shipping.
Shop NowFull Specifications
| Model | Antminer S21 Hydro |
| Model Number | S21 Hyd |
| Manufacturer | Bitmain |
| Algorithm | SHA-256 |
| Coins Mined | Bitcoin (BTC) |
| Hashrate | 335 TH/s |
| Power Consumption | 5,360 W |
| Efficiency | 16 J/TH |
| Noise Level | 50 dB |
| Chip Model | BM1368 |
| Cooling | Hydro |
| Voltage Range | 200-240V AC |
| Operating Temperature | 5-45°C |
| Dimensions | 412x197x209 |
| Weight | 15.8 |
| Interface | Ethernet |
| BTU Output | 18288.3 BTU/hr |
| Equivalent Heater | Equal to a 5,360W space heater |
| Daily Power Cost | $9.00/day |
| Monthly Power Cost | $270.14/mo |
| Circuit Requirement | 240V circuit required |
| Release Date | 2024-02-01 |
| MSRP | $9,500.00 |
| Status | Active |
Custom Power Profiles
With custom firmware like DCENT_OS, this miner can be tuned across a wide range of power levels. Lower wattage improves efficiency and reduces electricity costs; higher wattage increases hashrate at the expense of efficiency.
Performance Mode
| Wattage | Hashrate | Efficiency |
|---|---|---|
| 2,500 W | 148 TH/s | 16.9 J/TH |
| 2,900 W | 173 TH/s | 16.8 J/TH |
| 3,300 W | 197 TH/s | 16.8 J/TH |
| 3,620 W | 222 TH/s | 16.3 J/TH |
| 4,000 W | 247 TH/s | 16.2 J/TH |
| 4,370 W | 272 TH/s | 16.1 J/TH |
| 4,780 W | 297 TH/s | 16.1 J/TH |
| 4,980 W | 309 TH/s | 16.1 J/TH |
| 5,450 W | 334 TH/s | 16.3 J/TH |
| 5,800 W | 359 TH/s | 16.2 J/TH |
| 6,300 W | 383 TH/s | 16.4 J/TH |
Normal Mode
| Wattage | Hashrate | Efficiency |
|---|---|---|
| 1,630 W | 92 TH/s | 17.7 J/TH |
| 1,960 W | 109 TH/s | 18 J/TH |
| 2,280 W | 127 TH/s | 18 J/TH |
| 2,610 W | 145 TH/s | 18 J/TH |
| 2,930 W | 163 TH/s | 18 J/TH |
| 3,250 W | 181 TH/s | 18 J/TH |
| 3,580 W | 199 TH/s | 18 J/TH |
| 3,880 W | 217 TH/s | 17.9 J/TH |
| 4,210 W | 235 TH/s | 17.9 J/TH |
| 4,530 W | 253 TH/s | 17.9 J/TH |
| 4,860 W | 271 TH/s | 17.9 J/TH |
| 5,180 W | 289 TH/s | 17.9 J/TH |
| 5,500 W | 307 TH/s | 17.9 J/TH |
| 5,830 W | 324 TH/s | 18 J/TH |
| 6,150 W | 342 TH/s | 18 J/TH |
| 6,480 W | 360 TH/s | 18 J/TH |
Actual performance varies by individual unit silicon quality, ambient temperature, and cooling configuration. These operating points are achievable with custom tuning firmware such as DCENT_OS; values are calculated at runtime by the autotuner, not fixed presets.
Home Mining Assessment
Hydro-cooled S21 variant with 335 TH/s. Quieter than air-cooled models but requires water cooling infrastructure and 240V power.
The Antminer S21 Hydro is a SHA-256 cryptocurrency miner manufactured by Bitmain. It delivers a hashrate of 335 TH/s with a power consumption of 5360W, achieving an efficiency of 16 J/TH.
Built on the BM1368 ASIC chip, uses hydro cooling, operates at 50 dB noise level, weighs 15.8 kg, measures 412x197x209.
With a home mining score of 44/100, this miner is moderately suitable for residential use. It produces 18288.3 BTU/h of heat output, making it effective for supplemental space heating.
At 16 J/TH, the Antminer S21 Hydro sits in the current-generation efficiency tier, competitive with modern SHA-256 hardware (roughly 13-19 J/TH).
Its waste heat (around 18288.3 BTU/h) can be ducted into a room, turning money you would otherwise spend on heating into hashrate.
D-Central’s in-house technicians repair the Antminer S21 Hydro.
View detailed specifications, real-time profitability calculations, and comparison data for the Antminer S21 Hydro in our comprehensive ASIC miner database.
Antminer S21 specs, repair, and parts
Use the S21 cluster to connect current-generation specs, buying options, chip-level parts, troubleshooting, and repair support.
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Compare the Antminer S21 Hydro
Frequently Asked Questions
What are the current mining economics for the Antminer S21 Hydro?
At $0.07/kWh electricity, the Antminer S21 Hydro currently shows an estimated $0.44 daily net result before pool fees and hardware cost. Results depend on your electricity rate and Bitcoin network conditions. Use the calculator above with your actual electricity rate.
Can I mine Bitcoin at home with the Antminer S21 Hydro?
The Antminer S21 Hydro has a home mining score of 44/100. With 50 dB noise and 5,360W power draw, it may require a dedicated space like a garage, basement, or outdoor enclosure. Consider noise insulation and proper ventilation.
Can the Antminer S21 Hydro heat my home?
The Antminer S21 Hydro outputs approximately 18288.3 BTU/hr of heat. For reference, a typical space heater produces 5,000-5,500 BTU/hr. All electrical energy consumed by the miner is converted to heat, making it 100% efficient as a heater. D-Central offers Bitcoin Space Heater builds designed specifically for home heating integration.
Does D-Central repair the Antminer S21 Hydro?
Yes, D-Central provides professional repair services for the Antminer S21 Hydro. Services include hashboard repair, control board diagnostics, fan replacement, and full refurbishment. Ship your miner to our Laval, Quebec facility for diagnosis and repair.
What power supply does the Antminer S21 Hydro need?
The Antminer S21 Hydro draws 5,360W of power. You need a power supply rated for at least 5,896W with appropriate voltage (200-240V AC). D-Central stocks compatible power supplies in our shop. Always use a quality PSU from a reputable manufacturer to protect the miner and wiring.