Most people notice a dehumidifier the day the basement finally stops smelling damp. The electric bill is easier to miss. A dehumidifier is a compressor and a fan, and in a humid summer it can run for hours every day. So what does it really add to your bill?
Short answer: about 5 to 22 cents an hour for a typical home unit, which comes to roughly $11 to $53 a month at 8 hours of running time a day. The wide range comes from two things: the size of the unit and what you pay per kilowatt-hour. Here is the math, so you can swap in your own numbers.
How much power does a dehumidifier use?
Check the label or spec sheet for watts. One common ENERGY STAR line lists about 295 watts for a 25-pint unit, 490 watts for a 35-pint unit and 730 watts for a 50-pint unit. Another pair of models lists 600 and 900 watts for 35 and 50 pints. As a rule of thumb, expect somewhere between 300 and 900 watts while the compressor is running.
What a dehumidifier costs per hour
Cost per hour is watts divided by 1,000, multiplied by your rate. We use 16 cents per kWh (a lower-cost state) and 30 cents per kWh (a high-cost state), the same two rates as our space heater and mini fridge guides.
| Unit size | Typical watts | Per hour at 16¢ | Per hour at 30¢ |
|---|---|---|---|
| 25-pint | 295 W | 4.7¢ | 8.9¢ |
| 35-pint | 490 W | 7.8¢ | 14.7¢ |
| 50-pint | 730 W | 11.7¢ | 21.9¢ |
What it costs per day, month and season
A dehumidifier does not run nonstop. A built-in humidistat switches the compressor off when the room reaches your target, so think in running hours, not clock hours. The table assumes 8 hours of actual running time a day. Each cell shows the cost at 16¢ / 30¢.
| Unit size | Per day | Per month (30 days) | 4-month humid season |
|---|---|---|---|
| 25-pint | $0.38 / $0.71 | $11.33 / $21.24 | $45.31 / $84.96 |
| 35-pint | $0.63 / $1.18 | $18.82 / $35.28 | $75.26 / $141.12 |
| 50-pint | $0.93 / $1.75 | $28.03 / $52.56 | $112.13 / $210.24 |
A damp, cool basement can push these numbers higher. In cold rooms the unit spends more time defrosting its coils, and a leaky space keeps pulling in fresh moisture. At the other extreme, a small unit in a mildly humid bedroom may only run a couple of hours a day.
How to find out what yours really costs
There are two easy ways. Plug the dehumidifier into an energy-monitoring plug for a week, read the kWh total, and multiply by your rate. Or use our appliance running cost calculator with the wattage from the label and your own guess at daily running hours. Either takes about two minutes.
Six ways to lower the cost
- Size it to the space. A unit that is too small can run almost nonstop. One size up often reaches the target quickly and shuts off.
- Choose a realistic humidity target. Indoor humidity of roughly 30 to 50 percent is the usual advice, and 50 percent is the cheap end of that range. Every step lower means longer run times.
- Stop the moisture at the source. Seal gaps, close basement windows on muggy days, fix leaks and vent the dryer outdoors.
- Keep the room closed. A dehumidifier works best in one shut space, not a whole open floor.
- Keep it clean and give it room. Clean the filter and leave a little space around the unit so air can flow.
- Buy ENERGY STAR when you replace it. Certified models are built to remove more water per kilowatt-hour.
Thinking of putting it on a smart plug with a schedule? Check first that your model switches back on by itself after power returns. Many do not, and a timer on the wrong model just means it never restarts. Our automation and sensors guide covers smart plugs in more detail.
Is it worth the money?
For most homes, yes. The monthly cost is modest next to what mold cleanup or ruined stored belongings would cost, and a right-sized, ENERGY STAR unit keeps it as low as it can be. If you want to compare it with other appliances, see our guide to appliance running costs by state or the hidden cost of standby power.
