Bitmain Antminer S21 XP Hyd review
A 473 TH/s hydro miner that demands plumbing, a dry cooler, and a 240V circuit before it earns a single satoshi.
Bitmain Antminer S21 XP Hyd specifications
- Manufacturer
- Bitmain
- Released
- October 2024
- Hashrate
- 473 TH/s
- Power draw
- 5,676 W
- Efficiency
- 12.0 J/TH
- Electricity per day
- 136.2 kWh
- Cooling
- Hydro (liquid loop)
- Noise
- Low, pump and water loop only
- Algorithm
- SHA-256
- Estimated price
- $7,700 to $11,000
- Best for
- Serious and professional miners with water-cooling infrastructure already in place
Should you buy the Bitmain Antminer S21 XP Hyd?
Before an Antminer S21 XP Hyd hashes a single block, you have to build the system it lives in: supply and return plumbing for a closed coolant loop, a dry cooler or a cold water source able to reject nearly 5.7 kW of continuous heat, leak management wherever fittings meet electronics, and a 240V or higher circuit sized for 5,676 watts around the clock. None of that is optional, and none of it ships in the box.
What the loop buys you is density and quiet that air-cooled machines cannot match. Released in October 2024, the S21 XP Hyd runs 473 TH/s at 5,676 W, which works out to 12.0 J/TH, and because the heat leaves through water instead of fans, the unit itself makes no more sound than a pump and circulating coolant. It draws 136.2 kWh per day, so one chassis consumes what a small rack of older hardware used to.
The economics start after the build. As of August 2026 the machine sells for $7,700 to $11,000, and the plumbing, heat rejection, and electrical work are billed on top of that. On a network running about 910 EH/s as of August 2026, down roughly 19 percent from the November 2025 peak of 1,108 EH/s, 12.0 J/TH is the kind of efficiency that keeps a miner plugged in with difficulty at 127.48 T. But the S21 XP Hyd only delivers it inside infrastructure you have already paid for, so treat the water loop as part of the purchase price rather than an accessory.
Pros and cons
What works
- 12.0 J/TH efficiency, with 473 TH/s coming from a single 5,676 W chassis
- No fans on the unit: the only sound is the coolant pump and water moving through the loop
- Heat exits as warm water, which makes capture and reuse far more practical than air-cooled exhaust
- High density per rack slot: fewer machines, breakers, and network drops per PH/s of capacity
- Closed loop keeps dust and airborne humidity away from the hashboards
What to watch
- Cannot hash at all until you build a water loop: plumbing, a dry cooler or water source, leak management, and 240V or higher service
- 136.2 kWh per day means electricity dominates the math anywhere power is not cheap, about $13.62 daily at $0.10 per kWh
- $7,700 to $11,000 as of August 2026, with the cooling infrastructure billed on top
- A pump failure or leak stops mining immediately and puts water next to live electronics
How the Bitmain Antminer S21 XP Hyd compares
Frequently asked questions
How loud is the Antminer S21 XP Hyd?
Quiet by mining standards: the unit has no fans, so the only sound is the coolant pump and water moving through the loop. In practice the fans on your dry cooler, usually sited outdoors, end up being the loudest part of the installation.
What does the S21 XP Hyd cost to run per day?
About $13.62 per day at $0.10 per kWh. The miner draws 136.2 kWh per day, and 136.2 multiplied by $0.10 is $13.62, which comes to roughly $409 over a 30 day month. At $0.05 per kWh the same draw costs about $6.81 per day.
Can I run the S21 XP Hyd without existing water-cooling infrastructure?
Not realistically. The unit has no fans and no way to shed its own heat, so the minimum setup is a pump-driven coolant loop, a dry cooler or cold water source able to reject nearly 5.7 kW continuously, plumbing to and from the machine, and a 240V or higher circuit. Buying the miner first and improvising the loop later is how these units end up sitting idle.
Is 473 TH/s still competitive on the current network?
Yes, on efficiency. As of August 2026 the network runs about 910 EH/s, down roughly 19 percent from the November 2025 peak of 1,108 EH/s, and with difficulty at 127.48 T it is efficiency that decides which machines stay plugged in. At 12.0 J/TH the S21 XP Hyd sits at the efficient end of deployed hardware.