A dehumidifier runs for hours at a time, often for months, so its cost adds up in a way a quick glance at the wattage doesn't show. The cost depends on three things: how many watts it draws, how long it runs, and what you pay per kWh.
A typical 50-pint dehumidifier drawing about 590 watts, running 12 hours a day, uses about 7 kWh a day: about $1.27 a day or $38 a month at 18 cents per kWh. Over a four-month humid season that's about $153; running it year-round, about $459.
Dehumidifier Cost Calculator
Operating cost by season and over 5 years.
The formula
Cost = watts × hours ÷ 1,000 × price per kWh. At 590 watts for 12 hours, that's 7.08 kWh a day, or $1.27 at 18 cents. At the calculator's defaults the unit pulls about 25 pints of water a day, so each pint costs about 5 cents to remove.
How the calculator estimates run time
A dehumidifier cycles on and off as the room reaches the humidity you set. The calculator estimates daily run time from the gap between your current and target humidity and your climate, capped at the maximum hours you enter. It's an estimate: the real run time depends on how damp the room is and how much outside air leaks in.
The wattages are typical draws for each size; check your model's label for its own:
| Size | Typical draw | Cost per month at 12 hours a day |
|---|---|---|
| 30-pint | 300 W | $19.44 |
| 50-pint | 590 W | $38.23 |
| 70-pint | 700 W | $45.36 |
| 95-pint | 800 W | $51.84 |
| 110-pint | 900 W | $58.32 |
What each pint of water costs
Efficiency is where two units of the same size can cost very different amounts. The DOE rates dehumidifiers by Integrated Energy Factor (IEF), the liters of water removed per kWh, so a higher IEF means a lower bill for the same pints pulled.
A US pint is about 0.47 liters, so the energy to remove one pint is 0.47 divided by the IEF. At the ENERGY STAR minimum IEF for a large 50+ pint portable, 2.80, that is 0.47 ÷ 2.80 = about 0.17 kWh, or about 3 cents at 18 cents per kWh.
| Unit at its ENERGY STAR minimum IEF | IEF (L/kWh) | kWh per pint | Cost per pint at 18 c/kWh |
|---|---|---|---|
| Small portable, up to 25 pint/day | 1.57 | 0.30 | about 5.4 cents |
| Mid portable, 25–50 pint/day | 1.80 | 0.26 | about 4.7 cents |
| Large portable, 50+ pint/day | 2.80 | 0.17 | about 3.0 cents |
| Whole-house ducted | 2.09 | 0.22 | about 4.0 cents |
These are the minimums a unit must beat to earn the label, and the most efficient models do better. The example unit in the calculator above removes about 25 pints on 7.08 kWh, roughly 0.28 kWh a pint, which lands near the small-portable minimum.
Cost over a year
The annual cost follows how many months you run it. At the defaults:
| Use | Months | kWh per year | Cost per year |
|---|---|---|---|
| Humid season only | 4 | 850 | $153 |
| Spring through fall | 7 | 1,487 | $268 |
| Year-round | 12 | 2,549 | $459 |
Your electricity rate changes this more than anything else. The same default month costs about $26 at North Dakota's 12.36 cents per kWh and $98 at Hawaii's 46.28; see every state's average in our kWh cost calculator.
Three example cost scenarios
Where and how long a unit runs matters more than its size on the box. The three profiles below use the calculator's defaults and 18 cents per kWh, as examples.
- Damp basement, run year-round. A 50-pint unit at 590 watts for about 12 hours a day uses roughly 2,549 kWh, about $459 a year.
- Seasonal garage, four humid months. The same unit over a four-month season uses about 850 kWh, about $153.
- Crawlspace, small unit left on. A 30-pint unit at 300 watts running 24 hours a day is 300 × 24 ÷ 1,000 = 7.2 kWh a day, about 2,628 kWh and $473 across a year.
The crawlspace case costs more than the year-round basement despite the smaller unit, because it never cycles off. Run hours, not nameplate pints, drive the bill.
Carbon from running a dehumidifier
Running a dehumidifier draws grid electricity, so it carries a carbon cost alongside the dollar one. The EPA's eGRID figure for the U.S. average grid is 0.823 pounds of CO2 per kWh.
At the calculator's defaults, a four-month humid season of 850 kWh works out to 850 × 0.823 = about 700 pounds of CO2. Spring through fall, 1,487 kWh, is about 1,220 pounds; year-round, 2,549 kWh, is about 2,100 pounds.
A more efficient unit cuts this in the same proportion as the kWh, which is the strongest reason to size and set it well.
How to cut the cost
- Set it to 50%, not lower. The EPA recommends keeping indoor humidity between 30% and 50%, and below 60%. Every point lower means more run time for little benefit.
- Close the room. Shut doors and windows so it isn't drying the outdoors.
- Seal the leaks around basement rim joists, windows and vents that let humid air in.
- Size it right. An undersized unit runs nonstop; see what size dehumidifier you need.
- Keep the filter and coils clean, so air moves freely across them.
Frequently asked questions
How much does it cost to run a dehumidifier all day?
A 590-watt unit running 24 hours uses about 14 kWh, about $2.55 a day at 18 cents per kWh. Most run fewer hours because they switch off once the room reaches the set humidity.
How much does a dehumidifier add to the electric bill each month?
About $38 a month for a 50-pint unit running 12 hours a day at 18 cents per kWh. A smaller 30-pint unit costs about half that.
Does a dehumidifier use more electricity than an air conditioner?
No. A 3-ton central air conditioner at 14.3 SEER2 averages about 2.5 kW while it runs, roughly four times a 50-pint dehumidifier.
Should I run my dehumidifier all the time?
Let its humidistat decide. Set it to about 50% and it will run only as much as the room needs.
Is it cheaper to run a dehumidifier or the AC for humidity?
For pulling moisture specifically, a dehumidifier is cheaper, because it targets water directly while an air conditioner removes humidity only as a side effect of cooling. A 3-ton air conditioner averages about 2.5 kW while it runs, roughly four times a 50-pint dehumidifier. If you want drier air without colder air, the dehumidifier does the job for less.
Do ENERGY STAR dehumidifiers really save money?
Yes, if you run the unit a lot. A certified dehumidifier uses about 20% less energy than a comparable non-certified model, so a 50-pint unit that would cost about $459 a year run year-round saves roughly $92. The savings grow with run hours, so the label matters most for basements and humid climates.
How much does a whole-house dehumidifier cost to run vs a portable?
Per pint removed, a whole-house ducted unit at its ENERGY STAR minimum IEF of 2.09 costs about 4 cents, a little more than a large 50+ pint portable at 2.80, about 3 cents. A whole-house unit removes far more moisture and treats the entire home, so its total bill depends on how much water your house actually needs pulled. For a single damp room a portable usually costs less to run; for a consistently humid whole house the ducted unit is the practical choice.
Sources & References
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