Estimating Dehumidifier Energy Costs by Pint Capacity

Start with the integrated energy factor

The integrated energy factor (IEF) is the number that tells you how efficiently a dehumidifier turns electricity into removed moisture. ENERGY STAR defines it as liters of water removed per kilowatt-hour (L/kWh). A higher IEF means the unit removes more moisture for the same energy input, so it costs less to run for a given amount of drying.

The U.S. Department of Energy (DOE) sets minimum IEF standards for residential dehumidifiers. For units with a capacity up to 35 pints per day, the minimum is 1.35 L/kWh; that minimum rises to 1.50 for 35.01 to 45 pints, 1.60 for 45.01 to 54 pints, 1.70 for 54.01 to 75 pints, and 2.5 L/kWh for units above 75 pints. These numbers are a floor; many certified models exceed them, and ENERGY STAR certified models must meet even higher criteria. To learn more about the difference between IEF and the older energy factor, see our explainer.

Convert pint capacity and IEF into kilowatt-hours

To estimate the energy a dehumidifier uses, you start with its rated capacity in pints per day and its IEF. Because one pint is about half a liter, you can convert the daily capacity into liters, divide by the IEF, and get the kilowatt-hours the unit would consume if it ran at full rated output for 24 hours. For a 50-pint model running at its rated capacity, that works out to roughly 25 liters per day; at an IEF of 1.7, that is about 14.7 kWh per day. But you will rarely see that full-time draw, because the unit cycles on and off to hold a humidity setpoint.

The DOE test procedure changed in 2020 to measure capacity at 65°F instead of 80°F, so the pint rating on a new model is lower than the rating on an older comparable unit. When you estimate costs, use the capacity printed on the current spec sheet and the IEF that goes with it, not an older rating. If you need help locating these numbers, our guide to reading spec sheets explains where to find them.

Estimate how many hours the unit actually runs

The number of hours a dehumidifier runs each day depends on how much moisture is in the space. The CDC recommends keeping indoor relative humidity below 50% to prevent mold growth, and a dehumidifier with a humidistat will cycle to maintain whatever level you set. A damp basement with a high moisture load will make the unit run more hours than a slightly damp bedroom.

You can roughly estimate run hours by watching the unit for a few days, or you can assume that in a space that constantly feels damp, the unit will run most of the day. In a less demanding space, it might run a third of the day. Your local climate and the size of the room also matter. If you are dealing with a basement, see our sizing guide for large basements for more context.

Multiply by your local electricity rate

Once you have an estimate of daily kilowatt-hours, multiply it by the rate you pay for electricity. That rate is printed on your utility bill, usually in cents per kWh. If you do not know it, your utility company publishes it online. The result is the daily running cost.

Over a month, multiply that daily figure by 30. Keep in mind that electricity rates vary by region and can change over the year, so use the rate you actually pay. If you are on a time-of-use plan, the cost depends on when the dehumidifier runs. For more details on how energy consumption relates to wattage, see our article on dehumidifier electricity usage.

Compare models on cost per pint removed

The IEF gives you a direct way to compare running costs between models without needing to know the exact wattage. A unit with an IEF of 2.0 will use half the energy of a unit with an IEF of 1.0 to remove the same amount of moisture. ENERGY STAR states that certified dehumidifiers use 20% less energy than conventional models while removing the same moisture.

When you compare, look for the IEF on the spec sheet or the ENERGY STAR label. A model with a higher IEF will cost less to run per pint of water pulled from the air, even if its purchase price is higher. Understanding the ENERGY STAR program can help you evaluate those labels, so see our ENERGY STAR explainer.

Choose a capacity with running costs in mind

Larger dehumidifiers have higher minimum IEF standards under DOE rules, so they tend to be more efficient per pint removed. A 100-pint unit may cost more to buy, but it can also remove moisture faster, which means it cycles off sooner. In a large basement or a very damp space, a bigger unit can actually use less total energy than a smaller one that runs all day and never catches up.

The right approach is to match the capacity to the moisture load, then pick the most efficient model in that size class. Oversizing by one size is usually better than undersizing, because the unit will spend more time off. Use the tables in our best dehumidifiers for basements guide to see how different capacities compare.

What to pick for your use

Questions

What is the integrated energy factor (IEF)?

IEF is a measure of efficiency expressed as liters of water removed per kilowatt-hour of electricity consumed. Higher IEF means lower running cost per pint of moisture removed. ENERGY STAR uses IEF to rate dehumidifiers.

How do I find the IEF for a dehumidifier?

Look for the IEF on the product spec sheet, the ENERGY STAR label, or the manufacturer's online documentation. It is listed in liters per kWh.

Does a larger pint capacity always cost more to run?

Not necessarily. Larger units have higher minimum IEF standards, so they can be more efficient per pint. They may also cycle off sooner. The key is matching capacity to your moisture load and then picking the highest IEF in that size.

How can I estimate my dehumidifier's monthly cost?

Estimate daily runtime in hours, multiply by the unit's power draw in kilowatts, then by your electricity rate. Alternatively, use the IEF: daily pints divided by IEF gives approximate kWh, then multiply by your rate. Check your utility bill for the rate.

Why did the pint ratings change?

The Department of Energy updated the test procedure in 2020 to measure capacity at 65°F instead of 80°F, which better reflects basement conditions. New models may show lower pint ratings than older equivalents, so use the current rating when estimating costs.