Antminer S21 vs Bitmain Antminer S21+ Hyd
Side-by-side specs, profitability, and home mining comparison.
Specifications Comparison
| Antminer S21 | Specification | Bitmain Antminer S21+ Hyd |
|---|---|---|
| 200.0 TH/s | Hashrate | 319.0 TH/s |
| 3,500 W | Power Consumption | 4,785 W |
| 17.5 J/TH | Efficiency | 15.0 J/TH |
| 75 dB | Noise Level | 50 dB |
| 14.6 kg | Weight | 17.5 kg |
| 11,942 BTU/hr | BTU Output | 16,326 BTU/hr |
| 36/100 | Home Mining Score | 44/100 |
| — | Release Year | — |
| SHA-256 | Algorithm | SHA-256 |
| Bitmain | Manufacturer | Bitmain |
Profitability Comparison
Antminer S21
Bitmain Antminer S21+ Hyd
Based on BTC price of $78,244 and current network difficulty as of May 16, 2026. Actual results vary.
Verdict
Same generation, different cooling: the air-cooled S21 versus the hydro-cooled S21 Hyd. Water cooling promises quieter operation and better thermal management.
The S21 Hyd offers quieter operation and potentially higher sustained hashrate through superior cooling. However, it requires liquid cooling infrastructure that most home miners lack. The air-cooled S21 is simpler to deploy.
Spec Deltas
The Antminer S21 and Bitmain Antminer S21+ Hyd diverge on the metrics below — each gap expressed as a real percentage, not a vague "better":
- Bitmain Antminer S21+ Hyd 60% more hashrate (200 vs 319 TH/s)
- Antminer S21 27% better power draw (3,500 vs 4,785 W)
- Bitmain Antminer S21+ Hyd 14% better efficiency (17.5 vs 15.0 J/TH)
- Bitmain Antminer S21+ Hyd 33% better noise (75.0 vs 50.0 dB)
- Antminer S21 17% better weight (14.6 vs 17.5 kg)
- Bitmain Antminer S21+ Hyd 37% more heat output (11,942 vs 16,326 BTU/hr)
- Bitmain Antminer S21+ Hyd 22% more home mining score (36.0 vs 44.0)
Cost & ROI Over Time
Sticker price versus what the miner actually earns back: the table below projects cumulative net profit at a $0.10/kWh electricity rate.
| Antminer S21 | Metric | Bitmain Antminer S21+ Hyd |
|---|---|---|
| $5,500 | Upfront cost (MSRP) | $2,499 |
| -$1.20 | Daily net profit | $0.00 |
| -$5,938 | Net after 1 year | -$2,498 |
| -$6,375 | Net after 2 years | -$2,497 |
| -$6,813 | Net after 3 years | -$2,497 |
| Does not pay back at current rates (negative daily profit) | Payback period | Takes ~3,266.1 years to pay back at current rates |
Projections assume continuous operation, a flat $0.10/kWh rate, and no hardware degradation, pool fees, or BTC price change. Real-world ROI varies.
Best For...
Best for Profitability
Bitmain Antminer S21+ Hyd$1.20/day higher profit at current rates.
Best for Home Mining
Bitmain Antminer S21+ HydScore: 44/100. 50 dB noise level.
Best for Efficiency
Bitmain Antminer S21+ Hyd15.0 J/TH — lower electricity cost per terahash.
Frequently Asked Questions
Is the S21 Hyd quieter than the air-cooled S21?
Yes, significantly. The fans on hydro units run at lower speeds since liquid cooling handles most of the heat dissipation. However, the cooling system itself adds pump noise.
Do I need special infrastructure for the S21 Hyd?
Yes. You need a liquid cooling loop with a heat exchanger or dry cooler, coolant, pumps, and plumbing. This is typically only practical for commercial operations.