To estimate how much electricity a dehumidifier uses, divide its power in watts by 1,000, multiply by its actual operating hours, then multiply by your electricity price per kilowatt-hour (kWh). For example, a unit drawing a steady 350 watts for eight hours a day over 30 days uses 84 kWh. At an illustrative electricity rate of $0.18/kWh, that costs about $15.12 for electricity before taxes or other charges. The device’s real bill may differ because the compressor and fan cycle as humidity changes.
Dehumidifier electricity calculator: the formula
Use the same simple method recommended by the U.S. Department of Energy’s guide to estimating appliance electricity use:
Energy used (kWh) = (average power in W ÷ 1,000) × actual hours of operation
Electricity cost = energy used (kWh) × electricity price ($/kWh)
For monthly use when daily conditions are similar: monthly kWh = (watts ÷ 1,000) × hours/day × days/month. Use the current residential kWh rate from your own bill. The $0.18/kWh number in this article is a worked example, not a verified U.S. national average or your utility’s rate.
Daily and monthly dehumidifier cost examples
The following examples assume the appliance draws the stated power continuously during every listed hour. They are illustrations of arithmetic, not measured product performance or quoted 2026 electricity prices.
| Assumed draw | Hours/day | Monthly energy (30 days) | Cost at $0.18/kWh |
|---|---|---|---|
| 250 W | 4 | 30 kWh | $5.40 |
| 350 W | 8 | 84 kWh | $15.12 |
| 500 W | 12 | 180 kWh | $32.40 |
| 500 W | 24 | 360 kWh | $64.80 |
Running for 24 clock hours does not mean a properly controlled machine’s compressor necessarily draws its full rated wattage for all 24 hours. A humidistat may stop or restart the compressor; fans and controls can still draw smaller amounts of power. The amount of water removed, drainage method, room temperature, air leaks and target humidity all affect runtime.
Worked example: how much does a 350-watt dehumidifier cost?
- Convert watts to kilowatts: 350 ÷ 1,000 = 0.35 kW.
- For eight hours of continuous draw, energy = 0.35 × 8 = 2.8 kWh/day.
- For 30 equal days, energy = 2.8 × 30 = 84 kWh/month.
- At an illustrative $0.18/kWh, cost = 84 × $0.18 = $15.12/month.
If your electricity rate is $0.25/kWh instead, the same 84 kWh would cost $21.00. If a plug-in energy meter shows that the machine actually consumed only 50 kWh during the month because it cycled off, the energy portion would be $9.00 at $0.18/kWh. Using measured kWh is more reliable than guessing watts from the appliance’s capacity label.
Where to find your dehumidifier’s wattage
- Electrical rating label: Find the model number, voltage, frequency and rated input watts if listed. A rating in amps alone is not always a sufficiently accurate measure of real power because AC power factor matters.
- Manufacturer documentation: Check the actual model’s technical sheet for measured or rated input power; do not substitute another model’s specifications.
- Plug-in kWh meter: For a compatible appliance, a suitably rated meter can record consumption over a typical day or week, including cycling and standby power. Follow the meter’s and appliance’s electrical safety instructions.
- Utility data: Whole-home smart-meter readings can show a general change, but other appliances also consume energy, so they are not a direct per-device measurement.
The featured image shows an actual Maytag portable dehumidifier photographed in 2007. It does not identify the assumed 250 W, 350 W or 500 W devices in the examples. Its age and appearance do not establish today’s energy use or its ENERGY STAR status.
What does the ENERGY STAR dehumidifier efficiency rating mean?
ENERGY STAR evaluates qualifying dehumidifiers using Integrated Energy Factor (IEF), a standardized efficiency metric expressed in liters of water removed per kilowatt-hour (L/kWh). Higher L/kWh generally means a model removes more water per unit of tested electricity use; you should compare models under the relevant certification and capacity category.
The U.S. ENERGY STAR dehumidifier criteria state the Version 6.0 program requirements took effect on October 1, 2025. ENERGY STAR says certified models are more efficient than standard models, but a certification label is not a guarantee that a given household’s electricity bill will decrease by a fixed percentage. Humidity, runtime, temperature and sizing still matter.
Its separate testing and capacity guidance explains that capacity is measured in pints of moisture removed per day under defined conditions. Pints/day measure dehumidification capacity, not watts consumed. A 50-pint unit is not necessarily a 50-watt unit, nor does the capacity label mean 50 pints will be collected every day in your home.
Which humidity setting wastes less electricity?
ENERGY STAR describes a generally appropriate indoor relative humidity range of 30% to 50%; conditions above this range can encourage moisture problems. A setting around 45–50% RH may be a useful starting point if it prevents condensation and dampness, though individual rooms and climates can require different controls. In cold-weather homes, ENERGY STAR notes that lower indoor RH may help reduce window condensation.
Setting your dehumidifier to an unnecessarily low humidity level can force it to run longer. First use a hygrometer to learn your actual indoor RH; then choose the highest practical setting that avoids excessive moisture. Follow the device’s recommended room temperature and operating instructions.
Six ways to reduce dehumidifier running costs
- Fix moisture sources first. Repair plumbing leaks, reduce water intrusion and check exterior drainage. A dehumidifier cannot permanently compensate for an unresolved leak.
- Use a humidistat. Let the unit cycle as the target RH is achieved instead of running at maximum continuously.
- Choose an appropriate size. Match rated pints/day to your room’s size and dampness; oversized or undersized equipment can run inefficiently.
- Keep airflow open. Follow the manufacturer’s required clearance around intakes and discharge vents; clean the filter according to the manual.
- Consider verified efficient equipment. Compare models on the ENERGY STAR product guidance, checking model-specific efficiency and capacity.
- Monitor measured use. Check how many kWh the unit uses over representative days before deciding whether changed settings help.
Why a basement dehumidifier may cost more to run
A damp basement can continually receive moisture from the soil, foundation leaks, air infiltration or indoor activities. In that case, the machine must remove more water, so its compressor may run longer. Extremely cool rooms can also cause frost on some refrigerant coils, lowering water-removal performance until defrosting occurs. ENERGY STAR notes that rooms below approximately 65°F may require consideration of a low-temperature-rated machine.
If you have standing water, do not operate a standard plug-in appliance in contact with it or touch wet electrical outlets. Address water intrusion and electrical hazards safely before operating equipment. After a burst pipe, you may also want to read our separate homeowners insurance guide to sudden water damage.
Does a dehumidifier replace ventilation or mold remediation?
No. A dehumidifier can help manage airborne moisture in an otherwise suitable room, but it does not repair a leaking roof or foundation, remove contaminated materials or guarantee prevention of all mold. Use exhaust ventilation in bathrooms and kitchens, vent clothes dryers outdoors and address water damage promptly. EPA’s mold and moisture educational material describes the importance of controlling moisture and repairing sources.
If you are managing dampness alongside other indoor hazards, our radon testing guide explains a separate issue: removing moisture with a dehumidifier does not remove radon gas or replace radon testing.
Before you buy or change a setting: the cost checklist
- Find the unit’s actual rated power or measure its kWh use over several days.
- Check the complete electricity price from your own utility bill.
- Record room humidity and target RH, not just how full the water bucket becomes.
- Compare eligible ENERGY STAR models by capacity and IEF rather than by pints/day alone.
- Keep windows, vents, drainage and filter use consistent with the manufacturer’s instructions.
- Recalculate in wetter and drier seasons; continuous operation is not the same as full-power use.
Official references and related home-energy guides
Primary references: ENERGY STAR Dehumidifiers, ENERGY STAR Efficiency Criteria, Dehumidifier Testing and Capacity and DOE: Estimating Appliance Electricity Use. For an example of a different high-wattage household device, read our 1,500-watt space heater cost guide.
Editorial review: November 9, 2026. The example electricity rate and wattages are illustrative; they are not measured national averages or product specifications. Featured photograph: a real Maytag dehumidifier, Dchristle, public domain via Wikimedia Commons; no endorsement or certification is implied.
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How much does a 350-watt dehumidifier cost to run for eight hours?
At 350 watts of actual continuous draw for eight hours, usage is 0.350 × 8 = 2.8 kWh. Multiply 2.8 by your local $/kWh rate; at an illustrative $0.18/kWh, that is $0.50 for the eight hours.
Does a dehumidifier use electricity even when the compressor stops?
Some units still use power for fans, controls or standby functions. A meter over several days gives a better estimate than assuming every hour uses full rated compressor power.
What is the best humidity setting to avoid unnecessary energy use?
ENERGY STAR describes 30–50% relative humidity as a generally appropriate indoor range. Around 45–50% can be a reasonable starting setting depending on condensation, local conditions and the appliance's instructions.
What does L/kWh on an ENERGY STAR dehumidifier mean?
Liters of water removed per kilowatt-hour under the applicable standardized test. A higher Integrated Energy Factor generally indicates greater dehumidification efficiency under that test, not a promise of an exact household bill.
How many kWh does a dehumidifier use in a month?
Multiply its average measured power in kilowatts by the total hours it actually operates in a month. For instance, 0.35 kW × 8 hours/day × 30 days = 84 kWh if it draws 350 W for all those hours.
