Dehumidifiers can add a noticeable amount to an electric bill, but they do not all use the same amount of power. The real cost depends on the model’s wattage, how long its compressor runs, your humidity setting, room conditions, and your electricity rate. Checking the appliance label and doing a simple calculation gives you a much more reliable estimate than relying on pint capacity alone.
Quick Answer
A portable dehumidifier commonly uses a few hundred watts while its compressor is running. At $0.16 per kWh, a 500-watt unit costs about $0.64 for 8 hours, $19.20 for 8 hours a day over 30 days, or $1.92 if it runs continuously for 24 hours.
Key Takeaways
- Use the formula watts ÷ 1,000 × operating hours × electricity rate to estimate cost.
- Pint capacity measures moisture removal, not electricity use. Check watts, annual kWh, and Integrated Energy Factor when comparing models.
- A lower humidity setting, severe dampness, air leaks, blocked airflow, and an undersized unit can increase runtime.
- EPA recommends keeping indoor relative humidity below 60% and ideally between 30% and 50%.
- Actual consumption is best measured with a compatible plug-in electricity meter.
At a Glance
| Time Required | About 5 minutes to estimate cost |
| Difficulty | Easy |
| Tools Needed | Appliance label or manual, electricity bill, calculator, and optionally a compatible plug-in electricity meter |
| Cost | No cost with a calculator; the price of an optional electricity meter varies |
Why Do Dehumidifiers Use Electricity?
A compressor-style dehumidifier uses electricity to run a refrigeration system, fan, humidistat, display, and electronic controls. The fan pulls humid air across a cold evaporator coil. Water vapor condenses on the coil, drains into a bucket or hose, and the drier air returns to the room.
The compressor normally accounts for much of the running load. However, the unit may not draw its full rated power every minute because the compressor can switch off after the target humidity is reached. The fan may continue running on some models, and standby controls also use a small amount of electricity.
Dehumidifier efficiency is measured using Integrated Energy Factor, or IEF. IEF shows how many liters of water the machine removes per kilowatt-hour of electricity under standardized test conditions. A higher IEF means the unit removes more moisture for each unit of energy. Current ENERGY STAR dehumidifier criteria use IEF and include energy consumed during operating, standby, and off modes.
ENERGY STAR states that certified dehumidifiers are about 20% more efficient than non-certified models.
How Much Power Does a Dehumidifier Use?
Many portable compressor dehumidifiers draw a few hundred watts while actively removing moisture, but exact wattage varies by capacity, efficiency, fan speed, temperature, and design. Small specialty units may use less, while large portable, commercial, or whole-home machines may use considerably more.
Do not estimate power from pint capacity alone. Pint capacity tells you how much water the unit can remove in 24 hours under a specified test condition. It does not directly state how many watts the machine draws.
Where to Find the Correct Wattage
Check these locations in order:
- Appliance nameplate: Look on the back, side, inside the bucket compartment, or near the power cord.
- Owner’s manual: Search for rated input power, watts, amperage, or electrical specifications.
- Manufacturer specification sheet: Match the complete model number, not only the brand or pint rating.
- ENERGY STAR product listing: Certified listings may provide annual energy consumption and IEF.
- Plug-in electricity meter: This is the best way to measure actual household consumption over several days.
If the label gives amperage but not watts, multiplying volts by amps gives an approximate maximum input. This is not always the same as average measured consumption because motors, compressors, power factor, and cycling affect real use.
Pro Tip: Measure the unit for at least three to seven typical days. A one-hour reading may be misleading because humidity and compressor cycling change throughout the day.
Watts, Kilowatt-Hours, Capacity, and IEF
- Watts: The rate at which the appliance uses electricity while operating.
- Kilowatt-hours: The amount of electricity used over time. One kilowatt-hour equals 1,000 watts used for one hour.
- Pints per day: The amount of water a dehumidifier can remove during a standardized 24-hour test.
- Integrated Energy Factor: Liters of water removed per kilowatt-hour under the applicable test procedure.
The U.S. Department of Energy changed portable-dehumidifier test conditions beginning with newer ratings around 2020. Under the newer method, an older 70-pint portable unit is roughly comparable to a current 40- to 45-pint model, although the exact comparison varies by product. The ENERGY STAR testing and capacity guide explains these rating changes.
What Affects Dehumidifier Energy Costs?
Your operating cost depends on both the appliance and the moisture load in the building. Two identical machines can produce different electric bills when used in different rooms.
Rated Wattage and Efficiency
A high-wattage unit costs more per operating hour than a lower-wattage unit. However, wattage alone does not show how efficiently the machine removes water. Compare IEF, capacity, and annual energy consumption together.
Runtime
A unit that runs for 12 hours consumes about twice as much electricity as the same unit running for 6 hours. Runtime is affected by the humidistat setting, incoming moisture, room temperature, and whether the unit can reach its target.
Humidity Setting
Lower settings normally require more moisture removal and longer compressor operation. For general indoor moisture control, the U.S. Environmental Protection Agency recommends keeping indoor relative humidity below 60% and ideally between 30% and 50%. A target near 45% to 50% works well in many damp homes without over-drying the air.
Room Dampness and Moisture Entry
Leaks, groundwater seepage, wet foundations, unvented clothes dryers, indoor laundry drying, cooking, showers, and humid outdoor air can keep adding moisture. A dehumidifier then runs longer because it is treating the symptom while new water continues entering the space.
Doors, Windows, and Air Leakage
Leaving windows open in humid weather can make the machine work continuously. Close exterior doors and windows while the dehumidifier runs unless outdoor air is drier and intentional ventilation is appropriate.
Room Temperature
Cool air contains less moisture, and frost can form on the coils of some compressor dehumidifiers in a cold basement. ENERGY STAR advises checking for a model designed for lower temperatures when the space commonly falls below about 65°F. Repeated freezing and defrosting can reduce moisture removal and waste operating time.
Airflow and Maintenance
A dirty filter, blocked intake, dusty coil, or furniture placed too close to the discharge can reduce airflow. The machine may run longer while removing less water. Follow the manual’s cleaning schedule and maintain the required clearance around the unit.
Drainage Setup
Continuous drainage does not automatically reduce wattage, but it can prevent a full bucket from stopping the machine before humidity is controlled. Make sure a gravity hose slopes correctly and that a pump hose is installed according to the manufacturer’s instructions.
Note: Running a dehumidifier during off-peak hours lowers the bill only if your electric utility uses time-of-use pricing. It does not reduce the number of kilowatt-hours consumed.
How Much Does It Cost to Run One?
Use this formula:
Operating cost = watts ÷ 1,000 × operating hours × electricity rate per kWh
For monthly cost, multiply the daily result by the number of days used.
Example: 400-Watt Dehumidifier
A 400-watt unit used for 6 hours per day consumes:
400 ÷ 1,000 × 6 = 2.4 kWh per day
At $0.16 per kWh:
2.4 × $0.16 = $0.384 per day
For a 30-day month:
$0.384 × 30 = $11.52 per month
Estimated Monthly Cost at $0.16 per kWh
| Rated Power | 8 Hours Daily | 12 Hours Daily | 24 Hours Daily |
|---|---|---|---|
| 300 watts | $11.52 | $17.28 | $34.56 |
| 500 watts | $19.20 | $28.80 | $57.60 |
| 700 watts | $26.88 | $40.32 | $80.64 |
These figures assume that the stated wattage is drawn for every operating hour. A humidistat-controlled machine may consume less when the compressor cycles off, while a severely damp room may keep it running nearly continuously. Use measured kWh for the most accurate estimate.
Using Annual Energy Consumption
Some certified product listings provide estimated annual energy consumption. Multiply the listed annual kWh by your electricity rate:
Annual kWh × electricity rate = estimated annual cost
For example, an ENERGY STAR listing for one current 50-pint portable model reports 475 kWh per year. At $0.16 per kWh, that standardized estimate equals about $76 per year. Your result may differ because test assumptions cannot reproduce every climate, basement, humidity setting, or usage pattern.
How Can You Cut Dehumidifier Electricity Use?
- Choose enough capacity: Match the unit to both the room area and its dampness. ENERGY STAR generally advises that it is better to oversize than undersize a portable unit because an undersized model may run continuously without reaching the target.
- Compare IEF: Among units with suitable capacity, a higher IEF indicates more moisture removal per kWh.
- Use a practical humidity target: Start near 50% and lower it only when necessary to control condensation, musty odors, or a known moisture issue.
- Close the space: Keep windows and exterior doors closed during humid weather so the machine is not constantly treating incoming outdoor air.
- Fix moisture sources: Repair plumbing leaks, improve foundation drainage, vent clothes dryers outdoors, and use bathroom and kitchen exhaust fans.
- Clean the filter: Follow the manual’s maintenance interval. A blocked filter reduces airflow and moisture removal.
- Allow air circulation: Keep the intake and discharge clear. Follow the manufacturer’s wall-clearance instructions.
- Use built-in controls: A humidistat, auto mode, and built-in timer can prevent unnecessary operation. Do not bypass the manufacturer’s electrical instructions.
- Consider continuous drainage: A correctly installed hose or pump helps the unit operate without repeated bucket shutoffs.
- Measure before replacing: A plug-in meter can show whether the problem is high wattage, excessive runtime, or both.
How to Measure Actual Electricity Use
A compatible plug-in electricity meter records kilowatt-hours directly. This is more accurate than multiplying rated wattage by clock time because it captures compressor cycling, fan-only operation, and standby consumption.
- Confirm that the meter’s voltage, amperage, and wattage rating can safely handle the dehumidifier.
- Follow the dehumidifier manual and meter instructions.
- Reset the meter’s kWh reading.
- Operate the unit normally for at least three days, preferably a full week.
- Divide total kWh by the number of measured days to find average daily use.
- Multiply daily kWh by your electricity rate and by 30 for an estimated monthly cost.
Example: If the meter records 18 kWh over 6 days, average use is 3 kWh per day. At $0.16 per kWh, that equals $0.48 per day or about $14.40 per 30-day month.
Why Is My Dehumidifier Using More Electricity Than Expected?
Check these common causes:
- The target humidity is set very low.
- The unit is too small for the space or dampness level.
- Windows or exterior doors are open during humid weather.
- A plumbing, roof, drainage, or foundation leak is adding moisture.
- Laundry is drying indoors without ventilation.
- The filter or coil is dirty.
- The intake or outlet is blocked.
- The room is too cold for efficient compressor operation.
- The humidistat is inaccurate or located where it senses unusually damp air.
- The compressor does not shut off after the target is reached.
- The model is old or has a low IEF compared with current certified units.
If the compressor runs continuously after the room reaches the displayed target, the bucket repeatedly freezes, the power cord becomes hot, the unit smells like burning plastic, or it makes unusual electrical noises, turn it off and follow the manufacturer’s service guidance.
Warning: Dehumidifiers from several manufacturers have been recalled because they could overheat or catch fire. Check your brand, full model number, and date code on the U.S. Consumer Product Safety Commission dehumidifier recall page. Stop using any recalled unit and follow the official remedy instructions.
Frequently Asked Questions
Will a Dehumidifier Run Up Your Electric Bill?
It can create a noticeable increase if it runs many hours each day. A 500-watt unit running 8 hours daily costs about $19.20 per 30-day month at $0.16 per kWh. Actual cost may be lower or higher depending on compressor cycling, humidity, efficiency, and your electricity rate.
How Much Does It Cost to Run a Dehumidifier for 24 Hours?
At $0.16 per kWh, continuous operation costs about $1.15 for a 300-watt unit, $1.92 for a 500-watt unit, or $2.69 for a 700-watt unit. These examples assume the stated wattage is drawn for all 24 hours.
What Is the Downside of a Dehumidifier?
The main drawbacks are electricity use, fan and compressor noise, heat released into the room, filter and bucket maintenance, and the possibility of over-drying the air. A poorly sized or poorly maintained unit may also run for long periods without solving the underlying moisture source.
Should You Use a Dehumidifier if You Have COPD?
A dehumidifier may help when high humidity, mold, or dampness worsens your symptoms, but it is not a treatment for COPD. People have different temperature and humidity triggers, and air that is too dry may also feel uncomfortable. The American Lung Association identifies high humidity and weather extremes as possible COPD triggers. Discuss persistent breathing symptoms and your preferred indoor conditions with your healthcare provider.
Should a Dehumidifier Run All Day?
It may run for most of the day when first drying a very damp room. Once the target humidity is reached, a working humidistat should reduce compressor operation. Continuous long-term running can indicate a low setting, an undersized unit, incoming moisture, poor airflow, or a control problem.
Does a Larger Dehumidifier Always Cost More to Run?
A larger unit may draw more power while the compressor is on, but it can also remove moisture faster and shut off sooner. Compare suitable capacity, rated watts, IEF, and measured runtime rather than assuming the smallest model will have the lowest total cost.
Sources
- ENERGY STAR: Dehumidifiers — certified-unit efficiency, sizing, placement, drainage, temperature, and buying guidance.
- ENERGY STAR: Dehumidifier Efficiency Criteria — current IEF definitions and Version 6.0 qualification thresholds.
- ENERGY STAR: Dehumidifier Testing and Capacity — DOE test-method and capacity-rating changes.
- U.S. EPA: Care for Your Air — recommended indoor relative-humidity range.
- U.S. Consumer Product Safety Commission: Dehumidifier Recalls — recalled models and fire-hazard information.
- American Lung Association: Preventing COPD Flare-Ups — humidity, weather, and indoor-air triggers.
Conclusion
Dehumidifiers use a moderate amount of electricity, but the bill depends much more on wattage and runtime than on the pint number printed on the box. A 500-watt machine running 8 hours a day costs about $19.20 per 30-day month at $0.16 per kWh. Choose enough capacity, compare IEF, use a practical humidity target, maintain airflow, and fix moisture sources so the machine does not run longer than necessary. For the most reliable answer, measure actual kWh over several typical days and multiply that amount by your utility rate.
