Updated October 10, 2026. Rewritten with current network conditions, verified miner specifications, corrected payback math, and sources. Earlier versions linked to a live dashboard that is not available.
Choosing a Bitcoin miner is mostly a question of electricity. The April 2024 halving cut the block reward to 3.125 BTC, network difficulty sits near record levels, and big public miners are moving capacity toward AI data centers. For a small buyer, the machine you pick matters less than what you pay for every kilowatt-hour it burns.
I have operated an Antminer S21+ at a hosting facility in Washington State since July 2025, so this guide uses my own records where they help, and public data everywhere else.
The one number that matters: efficiency
A miner’s efficiency is measured in joules per terahash (J/TH): how much energy it uses to produce one unit of work. Lower is better. Two machines with similar hashrate can have very different electricity bills, and in the post-halving era that difference often decides whether a machine makes or loses money.
Where the network stands (October 2026)
- Difficulty: about 132.7 trillion, with the next adjustment expected around October 16 (CoinWarz)
- Network hashrate: roughly 890 to 935 EH/s over the past month (CoinWarz, Bitcoin.com)
- Bitcoin price: about $82,000 on October 10 (CryptoTimes)
- Hashprice: about $39 per petahash per day from block rewards alone, by our calculation at today’s difficulty and price. Bitcoin.com reported $39.63 in early September.
Current air-cooled miners for small buyers
Specifications and lowest listed prices from MiningNow’s October 2026 rankings. Prices move constantly; treat them as a snapshot.
| Model | Hashrate | Power | Efficiency | Lowest listed price |
|---|---|---|---|---|
| Antminer S21 XP | 270 TH/s | 3,645 W | 13.5 J/TH | $2,799 |
| Antminer S21 Pro | 234 TH/s | 3,510 W | 15.0 J/TH | $1,620 |
| Antminer S21+ | 235 TH/s | 3,877 W | 16.5 J/TH | $1,499 |
| Avalon Q | 90 TH/s | 1,674 W | 18.6 J/TH | $1,399 |
The S21 XP is the efficiency leader. The S21 Pro and S21+ offer similar hashrate at a much lower price, with the Pro using less power. The Avalon Q is built for home use: lower power draw and quieter, but far less hashrate.
What they earn at two electricity prices
The table below estimates daily block-reward revenue at today’s difficulty and price, minus electricity. It uses two rates: 7.4 cents per kWh, my hosting rate, and 21.84 cents, the average Maryland residential rate in October 2026 according to ElectricChoice. It excludes transaction fees, pool fees, downtime and hosting extras, so real results will be somewhat different.
| Model | Revenue/day | Net at 7.4¢ | Net at 21.84¢ |
|---|---|---|---|
| S21 XP | $10.49 | +$4.01 | −$8.62 |
| S21 Pro | $9.09 | +$2.85 | −$9.31 |
| S21+ | $9.13 | +$2.24 | −$11.19 |
| Avalon Q | $3.50 | +$0.52 | −$5.28 |
The pattern is the point: at a typical Maryland home rate, every one of these machines loses money every day. At a low hosted rate, they earn a few dollars a day. If nothing changed, an S21 Pro bought at the listed price would take about 19 months to cover its cost, and an S21+ about 22 months. Difficulty usually rises over time, so treat those as best cases, not forecasts.
My own S21+: what the records show
Over my first 155 days of operation, my S21+ earned about $1,621 in gross mining revenue, roughly $314 per 30 days. Hosting cost $209.60 a month at 7.4 cents per kWh, leaving about $104 a month before any other costs. I paid $3,953 for the machine including shipping, at 2025 prices. At that pace, recovering the hardware cost would take about 38 months.
Two lessons from that: hardware prices have fallen sharply since I bought (the same model now lists around $1,500), and margins are thin enough that a price drop, a difficulty jump or a few days of downtime can erase a month’s profit. Earlier versions of this guide suggested an 18 to 24 month payback; my own numbers did not support that, so I have corrected it.
Home mining or hosted mining?
If you pay more than about 10 cents per kWh, home mining with a full-size ASIC is unlikely to be profitable. Full-size machines are also loud (around 76 dB) and need 240-volt circuits and serious ventilation. Small home units like the Avalon Q are easier to live with but earn little.
Hosting providers run your machine in their facility for a monthly fee that usually includes power, cooling and basic maintenance. The trade-off is trust: you depend on the host’s uptime, honesty and business health, and repairs can take weeks. Check contract terms on downtime, repairs and getting your machine back before you sign.
The bottom line
- Compare machines by J/TH, not hashrate.
- Find your power price first, then run the math with today’s difficulty.
- Plan for margins to shrink as difficulty rises, and never count on a fixed payback date.
Sources
- MiningNow: Top 5 air-cooled Bitcoin miners (specs and prices, October 2026)
- MiningNow: Antminer S21+ specifications
- CoinWarz: Bitcoin difficulty (October 11, 2026)
- Bitcoin.com: Difficulty rises, hashprice up 22% (September 6, 2026)
- CryptoTimes: Bitcoin holds near $82K (October 10, 2026)
- ElectricChoice: Electricity rates by state (October 2026)
- Author’s own hosting invoices and pool payout records (first 155 days of operation, 2025)
This content is for informational and educational purposes only and is not financial or investment advice. The author owns an Antminer S21+ and holds BTC. Revenue estimates are calculations, not guarantees; verify current prices and difficulty before buying hardware.