The real cost depends on your dehumidifier's wattage and your local electricity rate

A typical dehumidifier uses between 300 and 700 watts. At the U.S. average electricity rate of roughly 16 cents per kilowatt-hour (though this varies significantly by region and season), running a mid-size 500-watt dehumidifier continuously for a month costs between $55 and $60. A smaller 300-watt unit runs about $35 to $40 monthly, while a larger 700-watt model reaches $80 to $85.

These numbers assume the dehumidifier runs at full power the entire time. In reality, most dehumidifiers cycle on and off based on the humidity level you set, so your actual bill will be lower than the continuous-run scenario. How much lower depends on your climate, how well your home is sealed, and whether you're running it in summer (when humidity is naturally higher) or winter (when indoor air is typically drier).

Key Takeaways

  • A 500-watt dehumidifier running 24/7 costs roughly $55 to $60 per month at average U.S. electricity rates, but rates vary by state and utility.
  • Most dehumidifiers cycle on and off automatically, so real-world costs are usually 30 to 50 percent lower than the continuous-run estimate.
  • Your actual monthly cost depends on three things: the unit's wattage (check the nameplate), your local electricity rate (on your utility bill), and how often the unit actually runs.
  • Dehumidifiers with a built-in humidistat and automatic shutoff use less energy than models without these features.
  • Running a dehumidifier in a sealed room costs less than running it in an open space, because the humidity level stabilizes faster.

How to find your dehumidifier's wattage

The wattage is printed on a label on the back or bottom of the unit, or in the manual. Look for a line that says "Power" or "Watts" — it will be a number followed by "W". If you cannot find it, the model number on that same label can be searched online with the manufacturer's name to find the spec sheet.

Do not confuse amps with watts. If you see only amps (marked "A"), multiply that number by 120 (the standard U.S. household voltage) to get watts. For example, a dehumidifier drawing 5 amps uses 600 watts.

Finding your local electricity rate

Your utility bill shows your rate in cents per kilowatt-hour, usually labeled "kWh" or "per kWh". Look for a line item that breaks down the cost per unit of energy — not the total bill, but the rate itself. Rates vary widely: some utilities charge 10 cents per kWh, others charge 20 cents or more. Seasonal rates also differ; summer rates are often higher than winter rates in the same region.

If you cannot find the rate on your bill, call your utility's customer service line (the number is on the bill) and ask for your current rate per kilowatt-hour. They can tell you in under a minute.

The math: calculating your monthly cost

Use this formula: (Watts ÷ 1,000) × Hours per month × Rate per kWh = Monthly cost.

For a 500-watt dehumidifier running continuously for one month (730 hours) at 16 cents per kWh: (500 ÷ 1,000) × 730 × 0.16 = $58.40. For a 300-watt unit: (300 ÷ 1,000) × 730 × 0.16 = $35.04. For a 700-watt unit: (700 ÷ 1,000) × 730 × 0.16 = $81.76.

If your rate is different, adjust the last number. At 12 cents per kWh, the 500-watt unit costs $43.80 monthly. At 20 cents per kWh, it costs $73.

Why your actual bill will likely be lower

Dehumidifiers with a built-in humidistat (a sensor that measures humidity) turn off automatically when the room reaches your target humidity level. Once the air is dry enough, the unit stays off until humidity rises again. This cycle means the compressor is not running the full 24 hours.

In a typical home, a dehumidifier might run 8 to 12 hours per day during humid months, cutting your monthly cost to $15 to $30 for a 500-watt unit. In winter or in a very dry climate, it may run only a few hours per week. The only way to know your actual usage is to check your utility bill before and after running the unit for a full month, or to use a plug-in power meter (available at hardware stores for $15 to $30) to measure how many kilowatt-hours the dehumidifier actually draws.

Energy-efficient dehumidifier features that lower your bill

Newer dehumidifiers often include features that reduce runtime. A built-in humidistat is standard on most models and is essential — without it, the unit runs constantly. Look for models with an automatic shutoff timer, which lets you set a maximum runtime even if humidity has not reached your target level.

Some units have a "low-temperature operation" mode that works in cooler basements or crawl spaces without freezing the coils. Others use a rotary compressor instead of a reciprocating one, which is quieter and slightly more efficient. Energy Star certified dehumidifiers meet federal efficiency standards, though the difference in cost between a certified and non-certified model is usually small.

The most effective way to lower your dehumidifier bill is to run it only in the room or rooms where you need it, with doors closed. A sealed space reaches your target humidity faster, so the unit cycles off sooner.

When 24/7 operation makes sense

Continuous dehumidifier operation is most common in basements, crawl spaces, or bathrooms where moisture is constant — not seasonal. If you have active water intrusion, a wet basement after heavy rain, or a crawl space with standing water, running the dehumidifier around the clock during those periods is necessary to prevent mold and structural damage. Once the water problem is fixed, you can reduce runtime.

If you are running a dehumidifier 24/7 and your electricity bill has jumped noticeably, the first step is to check whether the unit is actually needed at that intensity. A humidity meter (around $10 to $20) tells you the current moisture level. If it is below 60 percent, the dehumidifier can run less often. If it is above 70 percent and the unit is running constantly, you may have a ventilation or drainage problem that the dehumidifier alone cannot solve — that is the time to call a contractor.

Frequently Asked Questions

Does a dehumidifier use more electricity than an air conditioner?

No. A typical dehumidifier uses 300 to 700 watts, while a central air conditioner uses 3,000 to 5,000 watts. A window air conditioner uses 1,000 to 2,000 watts. Dehumidifiers are among the lower-cost appliances to run, though they do add to your bill if left on continuously.

Will a dehumidifier increase my electric bill noticeably?

If you run it 24/7, yes — expect $35 to $85 per month depending on the unit size and your electricity rate. If you run it with the humidistat on (so it cycles on and off), the increase is usually $10 to $30 per month. Check your bill before and after to see the actual impact.

Can I reduce the cost by running the dehumidifier only at night?

Only if humidity is lower at night in your climate. In most homes, humidity is fairly constant throughout the day. Running it only at night saves money but may not control humidity effectively. A humidistat does the job better — it runs whenever needed, whether day or night, and stops when the target is reached.

What if I leave my dehumidifier on but the bucket fills up?

Most dehumidifiers have an automatic shutoff that stops the unit when the collection bucket is full, so it will not overflow. The unit stays off until you empty the bucket. This means your 24/7 operation is interrupted by bucket-emptying cycles. If you want truly continuous operation, use a model with a drain hose that runs to a floor drain or sump pump.

Is it cheaper to run a dehumidifier or to use an air conditioner to dry out the air?

A dehumidifier is cheaper. An air conditioner does remove some moisture as a side effect, but it also cools the air — you are paying for cooling you may not need. A dehumidifier removes moisture without changing temperature, so it uses less energy for the same drying effect.