CAGI Isentropic Efficiency

CAGI Isentropic Efficiency

Before CAGI it was nearly impossible and confusing to compare two different air compressors with different rated discharge pressures and specific power (which is the energy consumption metric). However, this is no longer the case, CAGI has introduced an efficiency rating value on its Compressor Data Sheets – Isentropic Efficiency.


Utilizing isentropic efficiency is similar to using a Monroney window sticker when purchasing a new vehicle. For example, the Monroney sticker explains the projected miles per gallon of the vehicle, price, features, and other useful information that helps assist buyers when purchasing a new vehicle.

Isentropic efficiency incorporates operating pressure and greatly simplifies the process of comparing the efficiencies among several like-sized compressors each having slightly different full load operating pressures. For example, for the same horsepower compressors, one sheet may show 125 psi operating pressure and another may show 130 PSIG, so comparing isentropic helps equalize the comparison. This video, developed by the Compressed Air Gas Institute CAGI, explains how specific power is converted to isentropic efficiency.

For more information please visit Kaeser or Contact Us to speak with a specialist regarding your compressed air system needs. We have compressed air technicians available to assist you with calculations, installation, pricing, and more.