eCAPS
FAN ENERGY INDEX
Comprehensive Energy Metric
FEI is a comprehensive energy metric that goes beyond brake horsepower to include the impact of all components in the fan system including the aerodynamics, motors, VFD, drives, and bearings. Brake horsepower only considers the bearing and aerodynamic losses and ignores the rest of the fan system.
How is FEI Calculated?
FEI is simply the ratio of the Reference Electrical Input Power of a conceptual fan to the Actual Electrical Input Power of a fan system at the same duty point. The Reference Electrical Input Power is derived from actual historical fan sales data submitted by AMCA manufacturers and is intended to represent the typical power used at a specific duty point. The Actual Electrical Input Power is the power required to operate the actual fan system you are considering at the same duty point. An FEI >1.00 indicates your fan system uses less energy than the reference fan while a FEI<1.00 indicates it uses more energy than the reference fan.
If you want to dive deeper into the calculations behind FEI, read our application article.
Or let a manufacturer’s fan selection software, like Greenheck’s eCAPS®, do the work for you. Click HERE to access eCAPS and start selecting fans using FEI.
Select the Best Fan System
In addition to helping you compare and optimize the energy consumption of your fan system, FEI may also help you identify fan systems with better sound performance and more flexible operating ranges.
Quieter Operation
Flexible Operating Range
Selecting a fan with higher FEI means that you are relatively more central in the fan curve, which allows you more adjustment in the field if the installed duct system is different from your design intent.
Energy Efficiency
FEI is first and foremost an energy metric which allows you to compare the energy use of similar fan systems. For example, a fan system with an FEI value of 2.00 will use approximately 25% less energy than a comparable fan system with an FEI value of 1.50.
Codes and Compliance
Minimum FEI requirements are now included in the current ASHRAE 90.1 standard and International Energy Conservation Code (IECC). It is now up to states or local municipalities to incorporate these into their building codes. Since 2021, several states have incorporated the current 90.1 standard into their code, thereby setting minimum FEI values. Some states lack a state-level code but are seeing adoption at the municipal level. Navigating the complex landscape makes understanding how to comply with FEI codes and regulations difficult.
To stay ahead of these ever-changing codes, design to the latest versions of ASHRAE 90.1 and IECC and include and hold duty point FEI on your fan schedule.
Fan Efficiency Regulatory Journey
This timeline shows the journey FEI has taken from being published as a fan energy metric in AMCA 208 to being part of energy regulations in 15 states.
Adoption at State Level
As of January 7, 2025, 15 states meet the energy efficiencies established by the ASHRAE 90.1 2019 standard and have adopted it into their codes.
Source: https://www.energycodes.gov/infographics
Schedule and hold FEI values to stay ahead of changing codes.
To stay ahead of these ever-changing standards and regulations, update your specifications and schedules to include FEI even if your state has not yet adopted it. Greenheck recommends the following steps:
- Design to the latest versions of ASHRAE 90.1 and IECC.
- Include and hold duty point FEI on your fan schedule with a note stating, “Fans shall meet or exceed scheduled FEI value and be licensed to bear the AMCA Certified Ratings Program (CRP) seal for FEI.”
- Select the best fan. Visit eCAPS, Greenheck’s engineer application suite that includes FEI values, to find the most efficient fan system for your application.
See this example of how to optimize FEI on your fan schedule.
NOTES:
- Motors shall be high efficiency EC TYPE
- PROVIDE WITH 12” HIGH ROOF CURB
- FANS SHALL meet or exceed scheduled fei value and be licensed to bear the amca crp seal for FEI
Learn in Person
Reach out to your local Greenheck representative to arrange training on optimizing fan energy performance using FEI at a convenient location for you.