Prior to ASHRAE Standard 90.1-2019, fan efficiency was measured using the Fan Efficiency Grade (FEG) metric. While this metric was a helpful start, FEG resulted in inconsistencies and inaccuracies in defining the most energy-efficient fan for an application.
ASHRAE 90.1-2022 continues to require a more comprehensive fan energy-saving metric: The Fan Energy Index, or FEI. Unlike FEG, the FEI metric approach will enable better fan selection—inclusive of the effects of motors and drives—and design-point performance. This new metric is now being written into energy standards, adopted by state codes, enforced by code officials, and is further being considered for use in utility rebate programs.
Get up to speed on all things ASHRAE 90.1, FEG and FEI—including the benefits FEI offers engineers in selecting fans that will reduce energy consumption—in this two-part blog post from Greenheck: