CFM (Airflow)

CFM (cubic feet per minute) is the volume of air moved per minute by a fan, blower, or whole cooling system. It is the basic capacity metric for airflow: how much air you can push past hot components in a given time. Outside the United States the same quantity is often expressed in cubic metres per hour (m3/h) or litres per second.

CFM in ASIC and Hashcenter cooling

Every watt an ASIC miner consumes becomes heat that air has to carry away. Move too little air and chip temperatures climb, the autotuner throttles hashrate, and fans spin up trying to compensate. Mining fans are rated in CFM, and for an S19-class miner, intake fans in the 200-plus CFM range are typical. At the facility scale, total CFM must match the combined heat load of every miner on the floor, sized from the IT power draw and the desired temperature rise across the room.

CFM is only half the story

Raw CFM is measured in open, unobstructed air. The moment that air has to pass through a dense ASIC heatsink, a filter, or a contained aisle, resistance fights the flow and the delivered CFM drops. That is why a fan's CFM rating must always be read alongside its static pressure rating, the force available to push air through resistance. A high-CFM, low-pressure fan can move plenty of air in the open yet stall against a miner's heatsink.

Plan facility airflow by matching total system CFM to heat load, then confirm the delivery path with adequate air containment so the CFM you paid for actually reaches the chips.