When purchasing any appliance that is designed to move air you will encounter a specification for “CFM.” What does CFM stand for and how is it used?
CFM stands for “cubic feet per minute” and it measures the volume of air, in terms of cubic feet, that the device moves in a given minute.
Higher CFM devices will move more air than lower CFM ones. This is accomplished using a higher fan speed (usually measured in terms of revolutions per minute) or a larger fan diameter.
CFM vs SCFM
If you want to get technical SCFM is actually a more accurate measure of air volume moved because CFM doesn’t specify the conditions under which the air is moved. CFM is perfectly acceptable for the vast majority of use case, but in industrial and scientific settings you might see “standard CFM” (SCFM) which standardizes the conditions when the air is moved (temperature, type of gas being moved, and so forth).
CFM And Efficiency
CFM is not a measure of efficiency because it doesn’t take into account the amount of power being used in order to move that air. The corresponding efficiency measure is CFM per watt (CFM/watt). This measures how many CFM are produced given a single watt of power usage.
References
- HelpAtMyHome.com – Quietest Fan For Sleeping
- Wikipedia – Actual CFM