Air cooling
Air cooling is the classic ASIC setup: fans push air straight through the heatsinks on the hashboards. Cheapest way in, loudest way to live with.
What air cooling is
An ASIC turns nearly everything it pulls from the wall into heat. A 3.5 kW asic is a 3.5 kW space heater, and that heat has to go somewhere, nonstop. The air scheme solves it head-on: the chips press against heatsinks, and fans drive a stream of air through the case. S19 and S21 series asics carry four of those fans.
Its strengths are honest ones. Nothing leaks, nothing needs plumbing: set it on a shelf, plug it in, it runs. A fan costs little and swaps out with a screwdriver in ten minutes. That is why air-cooled asics outnumber everything else in the world, and in our catalog too: Bitmain alone has 48 of them out of 58.
The weaknesses are just as honest. A typical air-cooled asic sits around 75 decibels; you can't live with it in an apartment, and the neighbors hear it through the wall. Dust rides in with the airflow and the heatsinks clog up. And in hot weather the scheme hits its ceiling: you can't cool chips with hot air, so the firmware drops the frequency.
The short version
| Principle | heatsinks plus straight-through airflow across the case |
| Fans on the S19 and S21 | four |
| Noise | around 75 dB on a typical asic |
| Operating temperature | roughly -20 to +45 for Bitmain, -5 to +35 for MicroBT |
| Main upkeep | dust cleaning, fan replacement |
What the room decides
An air-cooled asic needs airflow, not floor space. A closed room heats up within hours, and from then on the ASIC just recirculates its own hot exhaust. The right layout takes cool air in on one side and dumps hot air outdoors on the other, easiest through opposite walls.
If you are counting on air conditioning, run the numbers first: it adds a quarter to a third of the removed load to your bill. Cooling a three-kilowatt asic with an AC means paying for roughly one more kilowatt. An exhaust duct is almost always cheaper.
Dust is an operating cost, not cosmetics. Clogged heatsinks push chip temperatures up, the miner drops frequency, and J/TH creeps upward. Blowing the dust out every few months brings the spec numbers back; in our workshop that is the most common "repair" on asics that come in.
Example
An Antminer S21 on air: 3500 W of heat, four fans, around 75 decibels. In a garage with an exhaust duct it lives happily; in a bedroom it is physically impossible. If the asic has to sit near people, look at hydro versions or desktop models rated in the hundreds of watts, there are no other quiet options on air.
Related terms
Where to go next on the site
Hardware
- Antminer S21 tool
- ASIC Miner knowledge base
Guides
Questions and answers
Can an air-cooled ASIC be made quieter
Not by much. Fan speed is dictated by chip temperature; slow the fans down and the asic drops frequency or trips its protection. What works is moving it to a non-living space, or sound insulation with proper airflow.
How often should the asic be cleaned
Depends on the site: every six months is enough in a clean room, every two or three months in a dusty shed or workshop. Chip temperature is your guide; if it creeps up in the same weather, time to blow the dust out.
What happens in a heat wave
The firmware drops frequency, so hashrate and income sag. In summer, air-cooled asics in closed rooms without an exhaust lose a noticeable share of their output, and that belongs in your math from the start.
A fan died but the asic keeps running. Is that bad
Yes. Uneven airflow overheats the nearest board, and the firmware does not always react in time. Replace a dead fan right away; it is the cheapest part in the asic anyway.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .