How much a dehumidifier costs to run depends on its wattage, how many hours per day it runs, and your local electricity rate
A typical dehumidifier uses between 300 and 700 watts. If you run a 500-watt unit for 8 hours a day in a region where electricity costs $0.12 per kilowatt-hour, you'll spend roughly $14.40 per month. A smaller 300-watt model running the same schedule costs about $8.64 monthly. A larger 700-watt unit costs around $20.16. The actual number depends on three things you can measure or find out: your dehumidifier's wattage (on the nameplate or manual), how many hours daily it actually runs, and your electricity rate (on your power bill).
Most dehumidifiers don't run continuously at full power. They cycle on and off based on the humidity level you set. A unit set to maintain 50% humidity in a damp basement might run 12 hours a day, while the same model in a slightly damp bedroom might run only 4 hours. This cycling means real-world costs are often lower than worst-case estimates.
Key Takeaways
- A 500-watt dehumidifier running 8 hours daily costs between $8 and $20 per month depending on your electricity rate.
- Your dehumidifier's wattage is printed on the back or bottom of the unit; electricity rates appear on your monthly power bill.
- Dehumidifiers cycle on and off automatically, so they rarely run at full power for the entire time they're plugged in.
- Larger units and longer daily run times increase costs, but running a dehumidifier is usually cheaper than the damage caused by excess moisture.
Finding your dehumidifier's wattage
The wattage is always printed on the unit itself. Look on the back panel, the bottom, or inside the door. It appears as a number followed by "W" — for example, "450W" or "600 watts." If you can't find it on the unit, check the manual or the manufacturer's website by searching for your model number.
Wattage varies widely by size and type. Compact units for small rooms (under 500 square feet) typically use 300 to 400 watts. Mid-size models for 500 to 1,500 square feet use 400 to 600 watts. Large units for basements or whole-house use can reach 700 to 1,200 watts. Refrigerant dehumidifiers (the most common type) generally use less power than desiccant models, which are designed for very cold or very dry environments.
Calculating your monthly and yearly cost
Use this formula: (Wattage ÷ 1,000) × Hours per day × Days per month × Electricity rate = Monthly cost. For a 500-watt unit running 8 hours daily at $0.12 per kilowatt-hour: (500 ÷ 1,000) × 8 × 30 × $0.12 = $14.40 per month, or about $172.80 per year.
Your electricity rate is on your power bill, usually listed as cents per kilowatt-hour (kWh). Rates vary by region and season. In the U.S., rates range from about $0.09 per kWh in Louisiana to $0.22 per kWh in Hawaii. If you're unsure, call your utility company or check their website. Once you know the rate, the math is straightforward.
To estimate yearly cost, multiply the monthly figure by 12. A $14.40 monthly cost becomes $172.80 annually. If you run the dehumidifier only during humid months (May through September in most climates), divide by 12 and multiply by the number of months you actually use it — roughly $72 for a 5-month season.
Why dehumidifiers cycle on and off
Dehumidifiers don't run constantly at full power. You set a target humidity level (usually 40% to 60%), and the unit measures the air. When humidity rises above your target, the compressor kicks on and removes moisture. Once the humidity drops to your target, the compressor shuts off. The fan may continue running briefly, but power consumption drops sharply.
This cycling means a dehumidifier plugged in for 24 hours might actually run at full power for only 6 to 10 hours, depending on how damp the space is and how well it's sealed. A very wet basement in summer will run longer than a slightly damp bedroom in winter. This is why real-world costs are often 30% to 50% lower than calculations based on continuous operation.
Comparing costs across different unit sizes
| Unit Size | Typical Wattage | 8 Hours/Day at $0.12/kWh | 12 Hours/Day at $0.12/kWh |
|---|---|---|---|
| Small (under 500 sq ft) | 300–400W | $8.64–$11.52/month | $12.96–$17.28/month |
| Medium (500–1,500 sq ft) | 450–600W | $12.96–$17.28/month | $19.44–$25.92/month |
| Large (1,500+ sq ft) | 700–1,000W | $20.16–$28.80/month | $30.24–$43.20/month |
These figures assume your electricity rate is $0.12 per kWh. If your rate is higher (say, $0.18 in the Northeast), multiply the monthly cost by 1.5. If it's lower (say, $0.09 in the South), multiply by 0.75. The table shows why choosing the right size matters: an oversized dehumidifier costs significantly more to run and often cycles on and off more frequently, which can wear out the compressor faster.
When the cost is worth it
Running a dehumidifier costs money, but not running one can cost far more. Excess moisture causes mold, which requires professional remediation (often $2,000 to $6,000). It rots wood framing, warps flooring, and damages drywall. It triggers allergies and asthma. A $15-per-month dehumidifier prevents these problems in most cases.
The cost is also temporary. You don't need to run a dehumidifier year-round in most climates. In the Northeast, Midwest, and Pacific Northwest, humidity is worst from May through September — five months. Running a unit only during that season cuts annual costs by more than half. In drier climates, you may need it only a few months or not at all.
Energy-efficient models with an ENERGY STAR label use 15% to 20% less power than standard units for the same capacity. The upfront cost is higher, but the savings add up over several years of use, especially if you run the unit frequently.
Frequently Asked Questions
Does a dehumidifier use more electricity than an air conditioner?
No. A typical dehumidifier uses 300 to 700 watts, while a window air conditioner uses 1,000 to 1,500 watts. A central air system uses 3,000 to 5,000 watts when running. Dehumidifiers are among the cheaper appliances to operate, though they run longer because they cycle based on humidity rather than temperature.
Will running a dehumidifier increase my electric bill noticeably?
A typical dehumidifier adds $10 to $25 per month to your bill, depending on size and run time. On a household bill of $100 to $150, that's a 7% to 20% increase. Most people find this acceptable compared to the cost of water damage or mold removal.
Can I reduce the cost by running the dehumidifier only at night?
Humidity doesn't follow a schedule, so running only at night usually doesn't work well. The unit won't remove moisture that builds up during the day, and humidity will spike again. Running it during the hours when humidity is highest (usually afternoon and evening) is more effective than running it on a fixed schedule.
What's the difference in cost between a small and large dehumidifier?
A small 300-watt unit costs roughly $8.64 per month at 8 hours daily. A large 700-watt unit costs about $20.16 monthly under the same conditions. The difference is about $140 per year. However, a unit that's too small won't lower humidity effectively, so you'll run it longer and use more power overall.
Do dehumidifiers with a pump cost more to run than models without one?
A built-in pump adds roughly 50 to 100 watts to the unit's power draw, increasing monthly cost by $1.50 to $3. However, a pump eliminates the need to empty a water tank manually, which is often worth the small extra cost, especially for units running 12+ hours daily.