Quick answer
The cost depends mostly on how much water the dehumidifier actually removes, not on its size. Divide the liters it removes by its efficiency (the Integrated Energy Factor, in liters per kWh) to get kWh, then multiply by your electricity price. As an example with assumed values, a unit that removes 10 pints (about 4.7 liters) a day at an efficiency of 2.0 L/kWh uses about 2.4 kWh a day; at the U.S. average residential price of 18.31 cents per kWh reported by the EIA for July 2026, that is roughly 43 cents a day, or about $13 a month if it runs like that every day.
What drives the running cost
Three numbers set what a dehumidifier costs to run:
- How much water it removes. A dehumidifier with a humidistat cycles off once the room reaches the target. A damp basement in August means many hours of running; a slightly damp bedroom in fall, far fewer.
- How efficiently it removes it. ENERGY STAR explains that efficiency is measured as the Integrated Energy Factor (IEF), in liters of water removed per kilowatt-hour; a higher IEF means a more efficient dehumidifier.
- What you pay per kWh. Prices vary widely by state and utility; your bill shows your rate.
Since IEF is liters per kWh, the energy used is simply the water removed divided by the IEF. That makes the calculation easy once you know roughly how much water you empty from the bucket.
Technical note: capacity is rated in U.S. pints per day, efficiency in liters per kWh. One U.S. pint is about 0.473 liters, so 10 pints ≈ 4.7 liters. IEF is measured under standard test conditions (portable units are tested at 65 °F); in a colder or drier room, real efficiency is typically lower, so treat any estimate as a floor rather than a ceiling.
The formula
Worked example
Assumed values: the unit removes 10 pints of water a day; its IEF is 2.0 L/kWh; electricity costs 18.31 cents per kWh (EIA, U.S. average residential price, July 2026).
- Water removed: 10 pints × 0.473 = 4.73 liters per day.
- Energy: 4.73 ÷ 2.0 = 2.37 kWh per day.
- Cost: 2.37 × $0.1831 ≈ $0.43 per day.
- Per 30-day month: about $13.
liters per day = pints per day × 0.473
kWh per day = liters per day ÷ IEF
cost per day = kWh per day × price per kWhIllustrative example. The water removed and the IEF are assumed values; replace them with your own. Price source: U.S. Energy Information Administration.
Cost scenarios
The table shows how the monthly cost changes with the amount of water removed and with efficiency, at the EIA’s July 2026 U.S. average of 18.31 cents per kWh. The IEF values match ENERGY STAR’s current minimums for portable units (see next section) plus a less efficient case for comparison.
| Water removed per day | IEF 1.5 L/kWh | IEF 2.01 L/kWh | IEF 3.30 L/kWh |
|---|---|---|---|
| 5 pints (2.4 L) | ≈ $8.70/month | ≈ $6.50/month | ≈ $3.90/month |
| 10 pints (4.7 L) | ≈ $17.30/month | ≈ $12.90/month | ≈ $7.90/month |
| 20 pints (9.5 L) | ≈ $34.60/month | ≈ $25.80/month | ≈ $15.70/month |
Two things stand out. The amount of water removed matters more than anything else: a unit working half as hard costs half as much. And efficiency makes a real difference over a season, especially in a basement that needs dehumidifying for months. For example, in the 10-pint row, going from 1.5 to 2.01 L/kWh saves about $4.40 a month; over a five-month humid season, that is roughly $22 on these assumed values.
What ENERGY STAR requires
ENERGY STAR’s current requirements (Version 6.0, effective October 1, 2025) set these minimum efficiencies for certified portable dehumidifiers. ENERGY STAR says certified models use about 20% less energy than similar conventional units.
| Portable dehumidifier capacity | Minimum IEF for ENERGY STAR |
|---|---|
| 25 pints/day or less | 1.70 L/kWh |
| 25.01 to 50 pints/day | 2.01 L/kWh |
| 50 pints/day or more | 3.30 L/kWh |
When comparing models, look for the IEF on the specification sheet or the ENERGY STAR product finder, not only the capacity.
How to lower the running cost
Ways to spend less
- Set a sensible target. ENERGY STAR considers 30–50% the optimum range. Setting 35% when 45% would do makes the unit remove more water for little benefit.
- Close doors and windows to the space, as ENERGY STAR advises, so the unit isn’t drying the whole house or the outdoors.
- Cut moisture at the source. The EPA recommends venting dryers outdoors and running exhaust fans when showering and cooking; every liter that never enters the air is a liter the dehumidifier doesn’t have to remove.
- Fix water problems. A leak or seepage can keep a unit running indefinitely.
- Keep it clean. A clogged filter or frosted coils reduce efficiency; ENERGY STAR notes frost can form on the coils when the air is cold.
- Choose an efficient model when buying: compare IEF, not just pints.
Measure your own cost
Estimates are only as good as their assumptions. For a real number, measure:
- Water: note how much you empty from the bucket each day for a week (a measuring cup works).
- Energy: a plug-in energy meter between the outlet and the dehumidifier shows kWh used over the same week.
- Price: take the total price per kWh from your bill, including delivery charges if they are per kWh.
- Multiply weekly kWh by your price and by about 4.3 for a monthly figure.
Watch out: plug the dehumidifier directly into a suitable wall outlet and follow the manufacturer’s instructions on extension cords. A plug-in energy meter should be rated for the appliance’s current.
Frequently asked questions
Does a bigger dehumidifier cost more to run?
Not necessarily. Cost follows the water removed and the efficiency. A larger unit that reaches the target and cycles off can cost the same or less than a small one that runs nonstop, especially since ENERGY STAR’s efficiency minimums are higher for larger portables.
Is it expensive to run a dehumidifier 24 hours a day?
With a humidistat, “on” 24 hours doesn’t mean the compressor runs 24 hours. The cost depends on how much water it removes; use the formula above with your own bucket measurements.
What electricity price should I use?
Your own, from your bill. The EIA publishes U.S. and state averages; the July 2026 U.S. residential average was 18.31 cents per kWh.
Is an air conditioner cheaper than a dehumidifier?
They do different jobs. Air conditioners remove moisture as they cool, but a cool, damp basement usually needs a dehumidifier rather than more cooling.
Sources
- ENERGY STAR. Dehumidifiers Key Efficiency Criteria: Version 6.0 minimum IEF.
- ENERGY STAR. Dehumidifiers: IEF definition, 20% less energy, humidity targets, doors closed, frost.
- ENERGY STAR. Dehumidifier Testing and Capacity: 65 °F test.
- U.S. Energy Information Administration. Electric Power Monthly, Table 5.6.A: average residential price, July 2026.
- U.S. EPA. A Brief Guide to Mold, Moisture and Your Home.
Next step
