What Is IEF (Integrated Energy Factor) on a Dehumidifier?
IEF (Integrated Energy Factor) is the current DOE-required efficiency rating for dehumidifiers, measured in liters of water removed per kilowatt-hour of electricity used. It replaced the older Energy Factor (EF) metric as part of the same 2019 rule that changed the capacity test from 80°F to 65°F. The key difference: IEF counts the power a unit draws even while cycled off, which EF ignored.
Why IEF exists
A dehumidifier with a humidistat cycles on and off as it reaches a target humidity level, but many units still draw a small amount of standby power while "off." The old EF metric only measured efficiency during active running time, understating real-world energy use. IEF folds in that standby draw, giving households a number closer to what actually shows up on the electric bill.
IEF and ENERGY STAR
ENERGY STAR certification for dehumidifiers is based on meeting a minimum IEF threshold, not on pint capacity. The higher "ENERGY STAR Most Efficient" distinction requires an even higher IEF. This means a smaller-capacity certified unit can be genuinely more efficient per pint removed than a bigger, uncertified one — capacity and efficiency are separate specs and should be checked separately.
What IEF doesn't tell you
IEF is an efficiency ratio, not a capacity number — it won't tell you whether a unit is big enough for your basement. Pair it with the correct pint capacity for your square footage and dampness level; see How Many Pints Do I Need for My Basement?
This page is an equipment-specification reference, not a health or mold-safety determination.
Frequently Asked Questions
IEF stands for Integrated Energy Factor — the current DOE-mandated efficiency metric for dehumidifiers, expressed in liters of water removed per kilowatt-hour of electricity consumed. It replaced the older Energy Factor (EF) metric alongside the 2019 test-procedure change.
EF measured efficiency only while the unit was actively running. IEF additionally accounts for the energy a dehumidifier draws while cycled off but still plugged in (standby power), giving a more complete real-world efficiency picture. Because of this, an EF figure from before 2019 is not directly comparable to a current IEF figure.
Not necessarily. IEF measures efficiency (moisture removed per unit of energy), while pint capacity measures total volume removed per day. A smaller-capacity, ENERGY STAR-certified unit can have a better IEF than a larger uncertified one — check both figures separately.
It's on the mandatory yellow EnergyGuide label required by the FTC on most dehumidifiers, and on ENERGY STAR's public certified-product list for units carrying that certification. Manufacturer spec sheets should also list it.