IEF, and what an ENERGY STAR badge is worth

What changed, and why it mattered

The old metric, Energy Factor, measured only the energy consumed while the compressor was running. That left a real loophole: a machine with a thirsty standby mode, or an inefficient fan that ran between compressor cycles, could post a respectable EF and still cost more to own.

Integrated Energy Factor, introduced alongside the 2019 test procedure, includes off-cycle energy. It is a harder test and a more honest one, and it is the reason the IEF figures you see now cannot be compared against EF figures from before 2020 any more than the pint ratings can. The 2019 change in full.

The real spread, measured

Read the IEF columns. Within a class the spread is modest: 2.01 to 2.20 across the 164 certified 50-pint models, 2.01 to 2.15 across the 21 certified 30-32 pint ones. The small classes are lower - 1.70 to 1.97 at 20-22 pints - because a smaller compressor is inherently less efficient at moving water.

That last point is worth dwelling on, because it inverts an intuition. A 50-pint machine is more efficient per pint of water than a 25-pint one, not less. It draws more per hour and moves more water per kilowatt-hour. When people say a big dehumidifier is inefficient, they mean it costs more per hour, which is a different claim.

What the badge is worth in money

ENERGY STAR's own claim is that certified dehumidifiers are about 20 percent more efficient than non-certified ones. Taking that at face value on a 50-pint unit: 488 W against roughly 610 W, which at twelve hours a day and the US average rate is about $8 a month, or $40 over a five-month season.

Real, and worth having, but smaller than the marketing implies and much smaller than the cost of getting the size wrong. It is also worth noting what certification gives you beyond efficiency: a certified model has its capacity and IEF published in a government dataset, which means those figures were verified rather than asserted. Four brands in our registry are absent from the list at some capacity, and for those units there is simply no published efficiency figure to check.

ENERGY STAR Most Efficient

A smaller subset of the certified list carries the Most Efficient designation, which is a higher bar renewed annually. In the current data those portables run to IEF 2.20 and the ducted whole-home units to 2.35 - against class medians of 2.01. Several are 25-pint units at IEF 1.85 or better, which is a large improvement on that class's 1.79 median.

The current ENERGY STAR dehumidifier specification took effect on 1 October 2025, so a unit certified before then was certified against the previous version. That does not make it inefficient - the published IEF is still the published IEF - but it is worth knowing when a listing leads with a badge rather than a number.

How to use IEF when buying

1. 1Compare within a class only. A 30-pint unit's IEF against a 50-pint unit's is not a comparison of efficiency, it is a comparison of size.
2. 2Convert IEF to watts if you want it to mean something. Liters per kWh is an abstraction; watts is a number you can multiply by your electricity rate. The formula.
3. 3Weight it by your electricity rate. At Nevada's 13.11 cents the spread within a class is worth a couple of dollars a month. At Hawaii's 52.72 it is worth having.
4. 4Do not let it override sizing. An efficient machine that is too small runs permanently and costs more than an average one that is right.