How Much Does a Dehumidifier Cost to Run Per Month? (2026 Data)

In WattCost's August 2026 snapshot of 519 certified models, the median dehumidifier consumes 338 kWh per year. At the U.S. residential average rate of 18.34¢ per kWh, that comes out to $5.17 per month during standard seasonal operation. High-capacity basement models run closer to 800 to 1,200 kWh annually ($12.23 to $18.34 per month), while whole-home crawl space units can reach $42.94 per month.

Key takeaways

• The median certified portable dehumidifier costs roughly $5.17 a month to run at 18.34¢ per kWh.
• Annual consumption across certified models spans from 105 kWh on compact units to 2,808 kWh on commercial crawl space systems.
• Basement placement in damp summer months often doubles duty cycles compared to standard test ratings.
• Running an older uncertified dehumidifier can cost three times more than a modern model certified under current Department of Energy test procedures.

Monthly running costs by model capacity

Dehumidifier power draw depends heavily on water removal capacity, measured in pints per day under the Department of Energy test conditions of 65°F and 60% relative humidity. In the WattCost dataset, small 20-pint to 30-pint portable models draw roughly 220 to 310 watts while actively compressing. At 8 hours of runtime per day, a 280-watt unit consumes 2.24 kWh daily, totaling about 67 kWh or $12.30 per month.

Standard 50-pint portable units draw between 420 and 540 watts. Because they remove moisture much faster, their internal humidistat shuts the compressor off sooner. A 50-pint unit running 5 hours a day consumes about 2.4 kWh per day, costing roughly $13.20 per month. You can browse individual model consumption numbers on the dehumidifier directory or check the most efficient dehumidifiers leaderboard to compare specific capacities.

Why basement humidity changes your electric bill

Manufacturer annual kilowatt-hour ratings assume standardized test schedules. In real homes, basements often sit near 70% to 80% relative humidity from May through September. If you leave a dehumidifier on continuous mode rather than setting the humidistat to 50%, the compressor runs 24 hours a day.

A 500-watt dehumidifier running continuously pulls 12 kWh every single day. Over a 30-day billing cycle, that single appliance uses 360 kWh, adding $66.02 to your monthly bill at national average rates. In higher-rate states like California or Massachusetts, continuous operation can easily exceed $110 per month. Setting the dial to a realistic 50% relative humidity target allows the unit to cycle off once the air stabilizes.

Integrated energy factor and efficiency ratings

The current metric for dehumidifier efficiency is the Integrated Energy Factor, or IEF. It measures the liters of water removed per kilowatt-hour of energy consumed (L/kWh). Higher numbers mean more water removed per dollar of electricity. Modern certified portable units typically score between 1.57 and 1.90 L/kWh, whereas units built before 2019 frequently scored below 1.20 L/kWh.

FAQ

How many watts does a standard dehumidifier use? Most portable home dehumidifiers use between 280 and 520 watts while the compressor is actively running. Fan-only mode uses roughly 30 to 50 watts.

Is it cheaper to leave a dehumidifier on all the time? No. Continuous mode forces the compressor to run nonstop even after the room reaches safe moisture levels. Using the humidistat set between 45% and 50% lets the machine cycle off, cutting electricity use by 40% to 60%.

What state electricity rates impact dehumidifier costs the most? Running a 400-kWh seasonal dehumidifier costs about $46 in Washington state (11.5¢/kWh), compared to $128 in California (32¢/kWh) and $176 in Hawaii (44¢/kWh).

Data notes & sources

Calculations use WattCost's August 2026 snapshot of 519 certified dehumidifiers and the U.S. EIA residential electricity benchmark of 18.34¢ per kWh.

Efficiency standards context: ENERGY STAR Dehumidifiers Program.

Electricity rates context: U.S. EIA Electric Power Monthly Table 5.6.A.