Should you buy one? The short answer first
Miners describe income with one number, hashprice: how much one unit of hashing power earns per day. On 6 November 2026 it was about $33 per PH/s per day. A PH/s (petahash per second) is 1,000 TH/s, so that is about $0.033 per TH/s per day, with bitcoin near $76,000 and the network near 1,035 EH/s (1 EH/s is 1,000 PH/s). For an Antminer S21 (200 TH/s, 3,500 W) that is about $6.65 a day. The machine uses 84 kWh a day, so it stops covering its own electricity at roughly $0.08 per kWh, before you pay anything for the machine itself.
Typical home electricity costs more than that: the US residential average is forecast at about 18 cents per kWh for 2026, and EU households paid on average about €0.28 per kWh in the first half of 2026. So for most people an ASIC is a loss-making hobby unless they have unusually cheap power or put the heat to real use. The profitability lesson shows how to redo this calculation with your own numbers, and keeps a dated table of today’s figures with where to check each one.
ASIC Mining Hardware in 2026
An ASIC miner is a machine built only to compute Bitcoin’s SHA-256 hashes (the mining lesson explains what that means). When you compare machines, three numbers matter: hashrate (TH/s, trillions of guesses per second), power draw (watts) and efficiency (joules per terahash, J/TH). Everything else is secondary.
Efficiency is the one to watch. J/TH tells you how much energy a machine needs for each trillion guesses. Since electricity is the largest running cost, a lower J/TH means more bitcoin earned per dollar of power, which decides whether a machine makes or loses money.
Three manufacturers make nearly all of Bitcoin’s mining hardware: Bitmain (China), MicroBT (China) and Canaan (founded in China, now based in Singapore and listed in the US). Bitmain is the largest by a wide margin. Competition among them keeps pushing efficiency down: the Antminer S9 of 2016–2017 needed about 98 J/TH, the S21 of 2024 needs 17.5 J/TH, and Bitmain’s S23 Hydro, shipping from early 2026, is rated at 9.5 J/TH. In November 2026 Bitmain is taking orders for an S23 XP Hydro rated at 8.9 J/TH, for delivery from that month.
The Antminer S21, which this lesson uses as its main example, was Bitmain’s mainstream model in 2024. In 2026 it is about two generations behind the best machines, but it is common, well documented and a good reference point.
A few terms you’ll meet
- Hashboard: the circuit board that holds the mining chips. A machine usually has three.
- PSU: power supply unit, which converts the mains supply for the hashboards.
- Hydro (liquid) cooling: water or coolant flows through plates on the chips instead of fans blowing air.
- Immersion cooling: the whole machine sits in a tank of non-conductive (dielectric) oil that carries the heat away.
- Autotuning, overclocking, underclocking: overclocking runs the chips faster (more hashrate, worse efficiency), underclocking slower (less hashrate, better efficiency). Autotuning firmware sets each chip’s frequency and voltage for the best efficiency at a power or hashrate target you choose.
Bitmain Antminer S21 Series
Antminer S21
The standard Antminer S21 delivers about 200 TH/s at about 3,500 W, an efficiency of 17.5 J/TH. It is air-cooled with built-in fans and runs at around 75 dB, about as loud as a vacuum cleaner that never stops. This is not a machine for a bedroom.
The S21 needs a 240 V circuit and draws about 15 amps. Setup is simple: connect power and Ethernet, open the miner’s web page from a browser on your network, enter your mining pool details, and it starts hashing.
Antminer S21 Pro and S21 XP
The S21 Pro (2024) does 234 TH/s at about 3,510 W, or 15.0 J/TH. The S21 XP (June 2024) does 270 TH/s at about 3,645 W, or 13.5 J/TH, and was Bitmain’s most efficient air-cooled model at launch. Both still need 240 V and the same noise and heat planning as the S21.
Antminer S23 (air-cooled)
The air-cooled Antminer S23 is Bitmain’s most efficient air-cooled machine in November 2026. Bitmain’s own listing gives 305 TH/s at 3,355 W, or 11 J/TH; retailers also sell a 318 TH/s version at about 3,500 W, with deliveries from January 2026. It runs on the same single-phase 220–277 V supply as the S21, and at about 76 dB at full fan speed it is just as loud.
Hydro-cooled models: S21 Hyd and S23 Hydro
Hydro models replace the fans with liquid cooling. They are far quieter, can run harder without overheating and fit more hashrate into less space. In exchange you need plumbing: a coolant distribution unit (the pump and control box), hoses and a way to get rid of the heat, such as a dry cooler outside. The S21 Hyd does 335 TH/s at 5,360 W (16 J/TH). The S23 Hydro, announced in May 2025 and shipping from the first quarter of 2026, is rated at 580 TH/s and 9.5 J/TH. The S23 XP Hydro, sold for delivery from November 2026, is rated at 600 TH/s and 8.9 J/TH. Both S23 hydro models run on three-phase 380–415 V power, and at 5–6 kW each these are machines for industrial sites, not homes.
MicroBT Whatsminer Series
MicroBT is Bitmain’s main competitor. Its Whatsminer machines have a reputation for solid cooling and sturdy power supplies, while Bitmain’s larger market share means more third-party firmware and an easier resale.
The Whatsminer M50S (about 126 TH/s at 3,276 W, around 26 J/TH) is an older air-cooled model now sold at a discount; it only makes sense with very cheap electricity. The Whatsminer M56S is an immersion-cooled machine: 212 TH/s at about 5,550 W, around 26 J/TH. It runs submerged in a tank of dielectric oil, not on a hydro coolant loop. MicroBT also sells hydro-cooled models.
Canaan AvalonMiner Series
Canaan made the first Bitcoin ASIC (the Avalon1, in 2013) and is listed on NASDAQ (ticker CAN). Its machines are less common on the second-hand market, which can make resale harder.
Canaan’s older AvalonMiner A14 series runs at about 150 TH/s and over 21 J/TH. Its current A16, launched in October 2025, does 282 TH/s at about 3,900 W (13.8 J/TH), and the A16XP 300 TH/s at 12.8 J/TH.
Canaan also sells the Avalon Q (March 2025), a small home miner built for household power: it accepts anything from 110 to 240 V, so it plugs into North America’s 120 V outlets as well as Europe’s 230 V ones. Its consumption is adjustable from about 800 W to roughly 1,600–1,700 W, for up to 90 TH/s, and it is designed to be quieter and to double as a heater. At full power it is about as efficient as an S21, so the economics above still apply: at typical home electricity prices it costs more to run than it earns, and the case for it rests on wanting the heat anyway. The lesson on home mining and mining scams looks at what else a newcomer can run at home.
A safety note on that household plug: at full power the Avalon Q pulls 13–14 amps from a 120 V outlet (about 7 amps at 230 V). That is more than the roughly 12 amps a common 15-amp household circuit should carry nonstop, and on a shared circuit it can trip the breaker or overheat old wiring. Run it at full power only on a dedicated 20-amp circuit, or use a lower power mode, and don’t share its circuit with other heavy appliances.
Why Three Manufacturers Dominate
A competitive mining chip has to be made on the most advanced manufacturing processes (5 nm and smaller). Only a few foundries, mainly TSMC and Samsung, can make them, and securing capacity takes large, long-term contracts. Several newcomers have tried to break in (Halong Mining, Ebang, Intel with its Blockscale chip, discontinued in 2023), but none reached the scale of the big three. The latest challenger is Bitdeer, a large mining company that also sells its own SEALMINER machines: its A4 series, launched in April 2026, is rated at 10.9 J/TH air-cooled and 9.45 J/TH hydro. The big three still form an oligopoly that supplies almost all of Bitcoin mining hardware.
ASIC Miner Comparison Table
Specifications from manufacturer data (Bitmain’s own shop for the S23 models) and Hashrate Index hardware overviews, checked on 6 November 2026. Prices are left out on purpose: they move with bitcoin’s price and change weekly, so check current listings before buying.
| Model | Manufacturer | Released | Hashrate (TH/s) | Power (W) | Efficiency (J/TH) | Cooling |
|---|---|---|---|---|---|---|
| Antminer S21 | Bitmain | 2024 | 200 | 3,500 | 17.5 | Air |
| Antminer S21 Pro | Bitmain | 2024 | 234 | 3,510 | 15.0 | Air |
| Antminer S21 XP | Bitmain | 2024 | 270 | 3,645 | 13.5 | Air |
| Antminer S21 Hyd | Bitmain | 2024 | 335 | 5,360 | 16.0 | Hydro |
| Antminer S23 | Bitmain | 2026 | 305 | 3,355 | 11 | Air |
| Antminer S23 Hydro | Bitmain | Ships 2026 | 580 | 5,510 | 9.5 | Hydro |
| Antminer S23 XP Hydro | Bitmain | Ships from Nov 2026 | 600 | 5,340 | 8.9 | Hydro |
| Whatsminer M56S | MicroBT | 2023 | 212 | 5,550 | 26 | Immersion |
| Whatsminer M50S | MicroBT | Older | 126 | 3,276 | 26 | Air |
| AvalonMiner A16 | Canaan | 2025 | 282 | 3,900 | 13.8 | Air |
| Avalon Q (home) | Canaan | 2025 | up to 90 | 800–about 1,670 | about 18–19 (derived, at full power) | Air |
The hydro and immersion rows draw over 5,000 W each, more than a typical home circuit is built for, and they also need pumps, hoses and an outdoor cooler (immersion adds a tank of dielectric oil); they are for sites with industrial power.
Where to Buy ASIC Miners
Buying a miner isn’t like ordering a laptop. The supply chain has its own habits, and scams are common.
Direct From Manufacturers
The safest option is to order directly from Bitmain (shop.bitmain.com), MicroBT (whatsminer.com) or Canaan (canaan.io). You get a warranty, genuine firmware and known hardware. The downsides: minimum order quantities may apply, lead times can stretch to months when demand is high, and you may have to arrange international shipping and import duties.
Authorized Resellers
Resellers in the US and Europe keep stock of current machines; Kaboomracks, Blockware Solutions and D-Central Technologies are examples (not endorsements). Expect to pay more than the manufacturer’s price in exchange for faster shipping and local support.
Used and Secondary Markets
Used miners can be much cheaper, but check:
- Hashboard condition: ask for photos and recent hashrate test results
- Firmware: stock firmware or a reputable third-party one; modified firmware may overclock the machine and shorten its life
- Warranty: most manufacturer warranties don’t transfer to a new owner
- Seller reputation: use escrow when buying from individuals
Scams to Recognize
These are the scams aimed at people buying or running mining hardware. The lesson on home mining and mining scams covers the wider family, from cloud mining to fake mining apps.
- Hardware that never ships: deals that look too good on social media, Telegram groups or unfamiliar websites. Stick to known platforms and verified sellers.
- Cloud mining contracts: you pay upfront for a share of someone else’s machines and are promised daily payouts. Many are Ponzi schemes that pay early customers with later customers’ money; treat any guaranteed return as a red flag.
- Fake hosting deals: a “hosting provider” takes your machine and fees but the machine is never plugged in, or is resold. Visit the site or use a provider with a verifiable track record.
- Malicious firmware: download firmware only from the manufacturer’s site or the firmware developer’s own site. Tampered firmware can quietly send part of your hashrate to someone else.
Timing Your Purchase
ASIC prices rise and fall with bitcoin’s price: in bear markets miners sell off machines cheaply, in bull markets demand outruns supply. A cheap machine bought in a downturn is still less efficient than next year’s model, and the next halving will cut every machine’s revenue in half.
What You Need Besides the ASIC Miner
Before you order a full-size ASIC, make sure you can run it.
Electrical Requirements
A full-size air-cooled ASIC like the S21 draws about 3,500 W, but Bitmain rates its input at up to 20 amps, so it needs a dedicated 240 V, 25–30 amp circuit, the kind used for an electric dryer or oven. A standard 120 V outlet can’t safely supply it. In most of Europe the mains is already 230 V, but 3,500 W still means about 15 amps nonstop, so the machine needs a circuit of its own. Small home units such as the Avalon Q are the exception: they run from an ordinary household outlet, even a 120 V one, at lower power and lower hashrate, though at full power on 120 V they still need a dedicated 20-amp circuit (see the safety note on the Avalon Q above). Have a licensed electrician install any new circuit. Several machines need serious upgrades: ten S21s need 35,000 W of dedicated capacity, which usually means three-phase power (the type of supply used by factories and large buildings).
Cooling and Ventilation
Almost all the electricity a miner uses becomes heat. A 3,500 W miner gives off about 12,000 BTU per hour, like a large space heater running flat out. In a closed room, temperatures climb fast. You need a way to bring cool air in and push hot air out, ideally in a garage, shed or other dedicated space. Above about 35°C (95°F) intake air, machines slow themselves down to protect the chips.
Noise Considerations
Air-cooled ASICs are loud. The S21 runs at around 75 dB, about as loud as a vacuum cleaner, around the clock. Most home miners put machines in a garage, basement or insulated outdoor box. Hydro and immersion setups are much quieter but need plumbing.
Network and Pool Setup
You need a stable internet connection (each miner uses only a few kilobytes per second) and a mining pool. The pool gives you a server address (a “stratum URL”) and port to type into the miner’s settings page; the pools lesson walks through it.
Mining Software
Miners come with firmware installed, and you configure them from a web browser at the miner’s local IP address. Third-party firmware such as Braiins OS+ and LuxOS adds autotuning (adjusting each chip’s power for the best efficiency) and more detailed monitoring.
Total Cost of Ownership
Beyond the purchase price, budget for:
- Electrical installation: $200–$2,000 or more for a 240 V circuit if you don’t have one
- Ventilation: $100–$500 for fans and ducting at home; far more for industrial cooling
- Electricity: see the monthly cost table in the FAQ below
- Maintenance: replacement fans, dust cleaning, occasional power supply repairs
- Hosting: if a third-party facility runs your machine, you pay an all-in rate per kWh that covers power, space and management
New miners often underestimate these costs. Run the full profitability analysis before buying.
Key Takeaways
- At November 2026 prices, an Antminer S21 stops covering its electricity at about $0.08/kWh, before the cost of the machine. Most home electricity is more expensive than that.
- Efficiency (J/TH) matters more than raw hashrate. The S21 (17.5 J/TH) is now about two generations behind the S21 XP (13.5), the Avalon A16 (13.8), the air-cooled S23 (11) and the hydro S23 models (9.5 and 8.9).
- Bitmain, MicroBT and Canaan make almost all mining hardware; Bitmain is by far the largest.
- Full-size ASICs need a 240 V dedicated circuit, ventilation and noise control. Small home units that run from an ordinary outlet, even a 120 V one, have lower hashrate and the same tight economics.
- Buy from manufacturers or established resellers, and treat cloud mining contracts with guaranteed returns as likely scams.
Frequently Asked Questions
Is the Antminer S21 the best ASIC miner in 2026?
No. It is a common, reliable reference machine, but the newest models need from about a fifth to about half less energy per terahash: 13.5 J/TH for the S21 XP, 11 for the air-cooled S23 and 8.9–9.5 for the hydro S23 models, against the S21’s 17.5. Whether it is a good buy depends on its price and your electricity: with very cheap power, an older machine bought cheaply can still earn back its cost; with average power, even the newest machine may not. Run the profitability calculation for your own rate.
How long do ASIC miners last?
The hardware can run for five years or more with good cooling, dust control and stable power; fans are the most common failure and are cheap to replace. The economic life is usually shorter, often two to five years depending on your electricity price, because newer machines and rising difficulty make old ones unprofitable.
Can I mine Bitcoin at home with an Antminer S21?
You can, but it is unlikely to pay. You need a 240 V circuit, a space that can take the heat and the noise, and electricity below about $0.08/kWh just to cover running costs at November 2026 prices. Noise is the biggest practical problem; at 75 dB the machine is too loud for any living space. Some people mine at home mainly for the heat, using it to warm a garage or workshop in winter. A small home unit that runs from an ordinary outlet is quieter and needs no 240 V circuit (on 120 V at full power it still wants a dedicated 20-amp one), but it does not change the arithmetic. The home mining lesson has more on mining at home.
How much does an ASIC miner cost to run per month?
An Antminer S21 at 3,500 W uses about 2,520 kWh a month if it runs nonstop. At $0.06/kWh that is $151/month; at $0.10/kWh, $252/month; at $0.18/kWh (close to the US residential average forecast for 2026), about $454/month. Compare that with the machine’s revenue, about $200 a month at November 2026 numbers. Revenue moves with bitcoin’s price and network difficulty, so check a current calculator before deciding.
Check Your Understanding
1. Two machines both make 200 TH/s. One is rated 17.5 J/TH, the other 13.5 J/TH. Which do you want, and why?
Answer
The 13.5 J/TH machine. Both earn the same bitcoin, because earnings depend on hashrate, but it uses about 23% less electricity to do it. Electricity is the main running cost, so the more efficient machine stays profitable at higher power prices and for longer as difficulty rises.
2. Hashprice is $0.033 per TH/s per day. An S21 uses 0.42 kWh per TH/s per day (17.5 J/TH × 24 hours ÷ 1,000). Roughly what electricity price makes it break even, ignoring the machine’s cost?
Answer
About $0.08/kWh: $0.033 ÷ 0.42 kWh ≈ $0.079. Above that, the machine costs more in electricity than it earns, even before you pay for it.
3. A website offers a “mining contract”: pay $1,000 today and receive a guaranteed $15 a day. What should worry you?
Answer
Real mining income can’t be guaranteed: it moves with bitcoin’s price, difficulty and fees, and $15 a day on $1,000 would beat any real machine by a wide margin. Promises like this are the typical shape of a Ponzi scheme that pays early customers with new deposits. You can’t check that the machines exist, and you would be handing your money to a stranger.