How Much Does a Dehumidifier Cost to Run? Per Hour, Day and Month

A typical home dehumidifier costs about 5 to 13 cents an hour to run, based on an average U.S. electricity price of around 18 cents per kilowatt-hour. A mid-size unit running 8 hours a day costs roughly $20 to $22 a month. Your real cost depends on the unit's wattage, how many hours it runs, and what you pay per kWh.

Dehumidifiers are not expensive to buy, but many people worry about what they will do to the electric bill. The good news is that the bill is easy to estimate. You only need three numbers: the watts on the label, the hours the machine runs, and your price per kWh. This guide gives you the numbers for common sizes, shows you how to do the sum for your own home, and explains what makes the cost go up or down.

The quick formula

Every appliance cost can be worked out the same way, and the U.S. Department of Energy uses this method in its own guide to estimating appliance energy use:

Watts × hours used ÷ 1,000 = kilowatt-hours (kWh). Then kWh × your price per kWh = cost.

Take a 500-watt dehumidifier that runs 8 hours in a day:

• 500 × 8 ÷ 1,000 = 4 kWh
• 4 kWh × $0.18 = $0.72 for the day
• Over 30 days, that is about $21.60

You can find the wattage on the label on the back or side of the unit, or in the manual. If the label only lists amps, multiply amps by volts (120 in most homes) to get watts.

Typical dehumidifier costs by size

Most home dehumidifiers draw somewhere between 300 and 700 watts while the compressor is running. Small units sit at the low end and big basement units at the high end. The table assumes 18 cents per kWh and a unit that runs 8 hours a day.

Those are working figures, not lab results. A particular model can draw more or less, so check the label. If your unit is rated for 600 watts, the middle row simply scales up: 10.8 cents an hour, or about $25.92 a month at 8 hours a day.

What if it runs all day and night?

Some people run a dehumidifier around the clock in a damp basement or a humid climate. If a 500-watt unit really ran 24 hours with the compressor on the whole time, it would use 12 kWh a day and cost about $2.16, or around $65 a month.

That is the worst case, though. A dehumidifier with a built-in humidistat stops the compressor when the air reaches your target. In a basement that has been dried out, the machine may only run a few hours out of 24. In a very damp room or in the middle of summer, it may run almost non-stop. So the honest answer to "what does it cost per month" is a range, and the range is set by how much moisture keeps coming into the room.

What changes the cost the most

1. The wattage of the machine

Bigger machines draw more power. But a bigger machine also removes water faster, so it may run for fewer hours. A unit that is far too small for the space can cost more overall, because it runs and runs and never reaches the target. If your room is large or very damp, a properly sized unit is often cheaper than a small one working flat out.

2. How many hours it runs

This is the biggest lever, and it depends on how much moisture enters the space. A leaking pipe, a damp crawl space, a dryer venting indoors, or drying laundry inside will all keep the humidity high. If you want to find out why the room stays damp, our guide to why the house feels humid even with the AC on walks through the usual causes, and hidden water leaks explains how to track down moisture you cannot see.

3. Your target humidity setting

The lower you set the target, the longer the machine runs. Many health and building guides suggest keeping indoor humidity roughly between 30 and 50 percent. Setting a dehumidifier to 30 percent in a damp climate can make it run almost all day, while 45 to 50 percent is often enough to stop mold and musty smells. Start at 50 percent, check how the room feels, and lower it a little only if you need to.

4. The temperature of the room

A standard compressor dehumidifier works best in a warm room. In a cold basement it removes much less water per hour and may ice up, so you pay for electricity without getting much water in the bucket. If that sounds like your machine, read why a dehumidifier runs but does not collect water.

5. How efficient the model is

Efficiency is measured in liters of water removed per kilowatt-hour. ENERGY STAR says certified dehumidifiers use about 10 to 20 percent less energy than standard models for the same water removal. Older units, especially ones that are 10 or more years old, tend to be less efficient, and worn parts make them worse.

6. Dirty filter or coils

A clogged filter or dusty coils make the machine work harder to move air. Washing the filter every few weeks and keeping the grilles clear is free and helps both the water output and the bill.

Is a dehumidifier cheaper than the damage it prevents?

Usually yes. Running a mid-size unit for $20 to $30 a month is far less than the cost of cleaning mold, replacing damp drywall, or throwing away clothes and furniture that smell musty. If you are already dealing with that smell, what to do about a musty room covers the cleanup that should go along with drying the air.

It does not make sense to run a dehumidifier to hide a real water problem. If the humidity returns within an hour of emptying the room, find the source of the moisture first. A dehumidifier is a tool for controlling humidity, not a repair for a leak.

How to measure your own dehumidifier's cost

If you want a real number instead of an estimate, you have three easy options:

1. Use the label. Read the watts, then use the formula above with the hours you think it runs per day. Remember the compressor does not run constantly, so this will be a slight overestimate.
2. Use a plug-in power meter. A cheap electricity monitor plugs into the wall, and the dehumidifier plugs into it. Leave it for a week and it will show the kWh used. Multiply by your rate and divide by seven for the daily cost.
3. Use your utility's app or smart meter. Many companies show hourly usage. Look at a day before and a day after you start the machine and compare.

The power meter is the most accurate for the money, and it works for any appliance in the house.

Seven ways to cut the running cost

1. Pick the right size. Match the unit's daily pint rating to your space and how wet it is, using the maker's chart. Too small means constant running, too big wastes money upfront.
2. Choose an ENERGY STAR model when you buy a new one. It costs a bit more at first and saves electricity every year.
3. Close the room. Shut doors and windows so the machine dries one space instead of the whole house.
4. Set the humidistat to about 45 to 50 percent and let the machine cycle.
5. Fix the moisture source. Seal leaks, vent the dryer and bathroom fans outdoors, and keep gutters and downspouts directing water away from the foundation.
6. Keep the filter and coils clean, and leave space around the unit so air can move freely.
7. Run it at the right time. If your electric company has cheaper off-peak hours, you can schedule the machine for them, as long as the room stays dry enough.

Dehumidifier or air conditioner: which is cheaper?

In a hot, humid season, your air conditioner also removes moisture as it cools. If the house feels sticky but the AC runs often, adding a dehumidifier can let you set the AC a degree or two higher while still feeling comfortable. But the AC is a much bigger power user, so the dehumidifier is only a saving if it reduces how long the AC runs. If the problem is a cold, damp basement, the AC does nothing there, and a dehumidifier is the right tool.

Should you worry about a high bill?

A dehumidifier is one of the cheaper appliances to run. If your bill has jumped a lot, the machine is rarely the whole story. Check other big users first, such as heating, cooling, a water heater, or an old refrigerator. If a space heater is the suspect, see what a space heater costs to run, because it uses about three times the power of a typical dehumidifier.

Also note any signs that the machine itself is failing. A unit that runs constantly but collects almost no water, trips the breaker, or makes new noises is wasting power. Why a breaker keeps tripping is worth reading if that is happening.

What we could not verify

Wattage varies by brand and model, and real consumption depends on room temperature, humidity and how often the compressor cycles. The cost ranges in this guide are estimates built from typical wattage and the average U.S. electricity price. Your own label and your own utility rate will give a more accurate figure.

The short version

A dehumidifier typically costs 5 to 13 cents an hour, about $13 to $30 a month at 8 hours a day, using an electricity price of 18 cents per kWh. To get your own number, multiply the label watts by the hours it runs, divide by 1,000, and multiply by your rate. Right-size the unit, choose ENERGY STAR, keep the filter clean, set the humidity to 45 to 50 percent, and fix the source of the moisture. That keeps the cost low and the room dry.