Understanding energy efficiency (J/TH): how to reduce your electricity costs with an Antminer S21+
In Bitcoin mining, everything revolves around one key indicator: the energy efficiencyexpressed in joules per terahash (J/TH)This figure determines how much electricity your miner consumes to generate a certain number of calculations. The better you understand it, the better you can control your profitabilityThis article explains how to interpret and optimize the J/TH on recent models like theAntminer S21+.
🔋 What is J/TH?
THE Joule by Terahash (J/TH) measures the amount of energy required to calculate one terahash (one trillion calculations). The higher this number is downThe more your machine is effective.
For instance :
- Antminer S19K Pro → 23.9 J/TH
- Antminer S21+ → 16.2 J/TH
- Antminer S21 Hydro → 15 J/TH
- Antminer S23 (2026) → approximately 11 J/TH
This improved efficiency allows for the production of more hashrate for the same consumption, therefore reduce your energy bill.
⚙️ Concrete example: operating cost according to the J/TH
Let's assume you're mining at an average electricity rate of €0.10/kWh.
| Model | Hashrate | Power | J/TH | Daily cost (€0.10/kWh) |
|---|---|---|---|---|
| Antminer S19K Pro | 120 TH/s | 2760 W | 23,9 | ≈ €6.62 / day |
| Antminer S21+ | 216 TH/s | 3564 W | 16,2 | ≈ €8.55 / day |
| Antminer S23 | 318 TH/s | 3498 W | ≈ 11,0 | ≈ €8.40 / day |
➡️ Result : For the same computing power, a newer ASIC consumes up to 40% less electricity than a 2022–2023 model.
💰 Calculate the actual profitability
Your net profit depends on:
- The daily BTC reward (TH/s × difficulty × BTC price)
- The energy cost (W × kWh rate)
- Network stability (overall hash rate)
To estimate your ROI, here is the simplified formula:
Net profit = (Daily revenue - (Power (kW) × Price kWh × 24))
With a SWith a 21+ kWh rate at €0.10/kWh and an efficiency of 16.2 J/TH, you can aim for a return on investment between 9 and 14 months based on the price of Bitcoin.
🌡️ How to improve your energy efficiency
- Optimized cooling: Lower the ambient temperature (between 15–25 °C) to reduce heat loss.
- Regular cleaning: Dust = heat = inefficiency.
- Use recent firmware: Bitmain updates its firmware to adjust voltage and optimize the J/TH ratio.
- Optimize the supply voltage: A stable network improves the consistency of the hashrate.
⚡ Focus : Antminer S21+ (216 TH/s, 3564 W, 16.2 J/TH)
THE S21+ is currently one of the best power-to-consumption ratios on the market. With its 216 TH/s for only 3564 Wit offers a 30% higher energy efficiency At S19K Pro, while remaining simpler to maintain than a Hydro model.
Its optimized 5nm SHA-256 architecture ensures excellent stability even under heavy load, and its air cooling makes it compatible with conventional farms.
👉 Available on Minent.fr with fast shipping from France.
🚀 Conclusion
By 2025, energy efficiency (J/TH) will be the number one profitability factor for any Bitcoin miner. Recent models such as theAntminer S21+ and the future S23 push the limits of efficiency while lowering electricity consumption.
Always keep an eye on the value J/TH before purchase: it directly translates your energy cost per terahash, and therefore your ability to remain profitable despite the evolution of the network.
Minent.fr – Your French partner for professional mining equipment: Bitmain, IceRiver, Goldshell and more.