Fan Energy Index

AMCA developed the fan energy index (FEI) in response to the 2013 U.S. Department of Energy (DOE) rulemaking, which preferred a metric based on electrical power consumption, different from the fan efficiency grade (FEG) metric.

FEI measures the efficiency of the entire fan system, including the fan, motor, and drive, instead of just the fan itself. It sets an efficiency and power baseline that changes with airflow and pressure and can be applied to most commercial and industrial fans and blowers.

This index is calculated using data from laboratory performance tests and can be found in manufacturer sizing software and product catalogs. Unlike other metrics, FEI does not set a peak-efficiency threshold but establishes a "range of compliant operations." This means that FEI optimizes fan, motor, and drive selections for the specific conditions under which they will operate.

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Benefits

Clarity for Buyers and specifiers

FEG ratings cover a range of sizes for a particular fan model, which can hide the lower actual efficiencies of smaller fans. For instance, the FEG 67 rating applies to a range of efficiencies, from approximately 45% to 65%, depending on the impeller diameter. Generally, larger fans are more efficient. To address this, designers need to use a sizing window to encourage fan selections to larger diameters. FEI ratings solve this problem by providing values that accurately reflect the actual efficiency of a fan.

Application Flexibility

Manufacturer software offers compliant fans of various types, sizes, materials, and motor/drive combinations when a designer inputs a fan selection or duty point. This makes cost-benefit analyses for fans with higher FEI ratings easier.

Simpler Design and Enforcement

FEG requires a sizing window of "15 percentage points from peak total efficiency." This means that fans must be rated for total efficiency although static-pressure ratings are more commonly used. For every fan that is being covered, designers must document it, and code officials must check for compliance. If the sizing window is ignored, smaller fan sizes will likely be selected because of lower costs, but this will result in higher energy consumption and life-cycle costs. On the other hand, FEI works for both static and total efficiency and eliminates the cumbersome window.

Greater Energy Saving

FEI saves energy compared to FEG by making it easier to use and enforce, and by encouraging the use of more efficient fan types, sizes, and motor/drive combinations.

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State Energy Codes & Updates

The latest editions of the U.S. model energy codes and standards have already made the transition to FEI, and it will be implemented as they are adopted.

For jurisdictions that adopt earlier editions of model codes, AMCA requests that they replace FEG provisions with FEI provisions.

If your jurisdiction follows the IECC, consider Florida - 2020 Florida Building Code, Energy Conservation, 7th edition - Section C403.2.12.3 Fan Efficiency. In doing so, they replaced the fan-efficiency section with the language in the 2021 IECC. View the IECC underlined-strikeout template.

If your area is updating to the 2013 or 2016 edition of ANSI/ASHRAE/IES 90.1, consider swapping the fan-efficiency section with the corresponding section in the 2019 edition. Oregon 2021 Oregon Efficiency Specialty Code (OEESC). Make changes to energy codes View the ASHRAE 90.1 underlined-strikeout template.