Running cost / Tool

Dehumidifier running cost calculator

Pick your unit size and your state, and the arithmetic is shown under the answer. Every default value on this page is visible and cited, which is the entire point.

By Scooter M.

Published September 1, 2026

Last updated September 1, 2026

The short answer

Cost per day equals watts divided by 1,000, times hours run per day, times your electricity price per kWh. A 50-pint unit at 488 W running 12 hours a day at the US average of 18.34 cents costs $1.07 a day and about $32 a month.

Running cost calculator

1. How many watts

watts

Use your unit's nameplate figure if it has one. If not, pick its DOE capacity class and we will load the median for that class:

Presets are median average draw computed across 527 ENERGY STAR certified portable models, from each model's published DOE capacity and Integrated Energy Factor. Retrieved 2026-09-01.

2. Hours a day

hours/day

12 hours is a reasonable figure for a correctly sized unit on a humidistat through a damp season. 24 is what an undersized one does, because it never reaches its target and never idles.

3. Your electricity rate

Rates are residential averages from EIA Electric Power Monthly, Table 5.6.A, June 2026. Source. Your own tariff will differ - take the figure from a recent bill by dividing the total cost by the kWh used.

488 W, 12 h/day, US average at 18.34 cents/kWh

$32.69

Per month

Per day: $1.07
Per kWh/day: 5.86
Five-month season: $163.46
Per year, at this rate: $392.01

The formula

(488 W / 1000) x 12 h x $0.1834/kWh = $1.07 per day

$1.07 x 30.44 days = $32.69 per month

No number is used here that is not shown, and no number is shown without its source. That is the whole design brief for this page.

A calculator and pen on a dark desk surface — Every default on this page is on screen with its source. That is the design brief.

Why every default here is on screen

Because the alternative is what happened to this category. The most-cited dehumidifier running-cost calculator on the web is currently offline pending re-verification, and the main working alternative ships a 46 W default for a dehumidifier.

Forty-six watts is roughly a tenth of what a real 50-pint unit draws. The certified median across 164 models is 488 W. A calculator with that default tells its users their dehumidifier costs about three dollars a month, and because the default is invisible, nobody can see why the answer is wrong.

10x

How far off an invisible default can be

A 46 W dehumidifier default against a certified 50-pint class median of 488 W. Class median computed from the ENERGY STAR certified product list, 2026-09-01.

So the rule for this page is simple: no number is used that is not shown, and no number is shown without its source. The wattage presets come from the ENERGY STAR certified list. The electricity rates come from the EIA. Both are named on screen with their vintage, and you can overwrite either.

What to put in each field

Watts. If your unit publishes one, use it. If not, pick the DOE capacity class and the calculator loads that class's certified median. The full wattage table shows every class and its range.
Hours per day. Twelve is a reasonable figure for a correctly sized basement unit on a humidistat through a damp season. Twenty-four is what an undersized one does, and if that is your situation the real fix is a bigger machine. Four to six suits a unit run only when the room is occupied.
Electricity rate. Pick your state and the calculator loads the EIA residential average. Your actual tariff will differ - check a bill, because time-of-use plans in particular can be far from the state average.

The two things that change the answer most

Your state. Nevada residential electricity is 13.11 cents per kWh and Hawaii is 52.72. That is a factor of four on the identical machine doing the identical job. The state you live in matters more to your running cost than which 50-pint unit you buy. Rates by state.

Whether the machine is correctly sized. Every figure this calculator produces assumes the unit reaches its humidity target and idles. An undersized machine never does - it runs flat out, permanently, and the hours-per-day field should read 24. That is why a 30-pint unit in a wet basement costs more to run than a 50-pint one. Sizing.

What this calculator will not tell you

How many hours yours will actually run. That depends on the room, the season, the target you set and how well the space is sealed. Nobody can compute it from a spec sheet, and a calculator that claims to is guessing.
Your exact tariff. State averages are averages. A time-of-use plan, a fixed supply charge or a demand charge will all move your real number.
Cost per pint removed, unless you know your unit's actual extraction rate rather than its rated one. Rated capacity assumes 65F and 60% RH; in a drier room the machine removes less water for the same power, so the real cost per pint is higher than the rated one.

FAQ

Questions

How much does it cost to run a dehumidifier per day?

A 50-pint unit at 488 W running 12 hours costs $1.07 a day at the US average rate of 18.34 cents per kWh. A 30-pint unit at 318 W over the same hours costs $0.70.

How do I find my dehumidifier's wattage?

Check the nameplate on the back or the specification section of the manual. Most makers do not publish it - of 21 units in our registry, one prints a wattage on its listing. Where none exists, use the certified median for the capacity class.

Is it cheaper to run a dehumidifier at night?

Only on a time-of-use tariff, where off-peak rates can be substantially lower. On a flat rate the time of day makes no difference to the cost, though it can make a difference to the noise.

Does a dehumidifier use more electricity than a fridge?

Per hour of running, usually yes - a 50-pint dehumidifier averages 488 W against a modern fridge's compressor at roughly 100 to 200 W. Over a year a fridge often uses more, because it runs continuously all year and the dehumidifier runs for one season.

Sources