Cost to Run a Dehumidifier: Watts, kWh and Monthly Bill

A damp basement can make a whole house smell musty, warp hardwood and encourage mold, so many homeowners run a dehumidifier from spring through fall. The cost to run a dehumidifier is usually modest but not trivial: a typical 50-pint portable unit draws around 500 to 700 watts while its compressor runs, which works out to roughly 9 to 12 cents an hour at an example rate of 17 cents per kWh. Over a month of steady use, that often lands somewhere between $15 and $40.

The wide range comes from how long the compressor actually runs. A dehumidifier with a built-in humidistat shuts off once the room reaches its target humidity, then restarts as moisture creeps back. In a tight, finished basement it may run only a third of the day. In a damp, unfinished space with a dirt crawlspace next door, it may run almost constantly through July and August.

Electricity rates also vary widely by state and utility, so the examples here are a starting point. Plug in your own rate and you will have a realistic estimate in a couple of minutes.

Typical Wattage and the Cost to Run a Dehumidifier by Pint Size

Dehumidifiers are sold by how many pints of water they can remove in a day under standard test conditions. Larger capacity means a bigger compressor and more power draw, but also more water removed per hour, so a properly sized larger unit may run fewer hours.

The exact dehumidifier electricity usage varies by model and conditions. Wattage climbs a little in warm, very humid air and drops when the fan runs alone after the compressor cycles off. Check the rating plate or the product manual for your unit’s watts or amps (amps × 120 = approximate watts).

How to Calculate Your Own Dehumidifier Cost

The formula is the same one used for any appliance:

Watts × hours ÷ 1000 × rate per kWh = cost

1. Find running watts. Say your 50-pint unit is rated 600 W.
2. Estimate compressor hours per day. If the humidistat keeps it running about 12 of 24 hours, use 12.
3. Convert to kWh. 600 × 12 ÷ 1000 = 7.2 kWh per day.
4. Multiply by your rate. 7.2 × $0.17 = about $1.22 per day.
5. Scale to a month. $1.22 × 30 = about $37 per month.

Rates vary, so swap in your own. At 12 cents per kWh, the same example is about $26 a month. At 30 cents, about $65.

Daily and Monthly Cost Examples

These assume the example rate of 17 cents per kWh.

• 22-pint unit at 300 W, 10 hours a day: 3 kWh daily, about $0.51 a day, roughly $15 a month.
• 35-pint unit at 450 W, 12 hours a day: 5.4 kWh daily, about $0.92 a day, roughly $28 a month.
• 50-pint unit at 600 W, 8 hours a day: 4.8 kWh daily, about $0.82 a day, roughly $24 a month.
• 50-pint unit at 600 W, 24 hours a day: 14.4 kWh daily, about $2.45 a day, roughly $73 a month.
• Whole-house unit at 800 W, 10 hours a day: 8 kWh daily, about $1.36 a day, roughly $41 a month.

So how much does it cost to run a dehumidifier in a typical basement? For most homes with a correctly sized unit and a reasonable humidity setting, expect somewhere in the $15 to $40 monthly range during humid months, and much less in dry winter months when it barely runs.

Are Dehumidifiers Expensive to Run?

Compared with central air conditioning or an electric water heater, no. A dehumidifier typically uses a fraction of the power of a central AC system. Compared with a refrigerator, a dehumidifier running half the day often uses more energy, because a modern fridge averages only around 1 to 2 kWh a day.

The bigger question is value. Running a dehumidifier to hold a basement at 45 to 50 percent relative humidity helps protect flooring, drywall, stored belongings and wood framing from moisture damage. Mold remediation, cupped hardwood or ruined carpet padding costs far more than a season of electricity. Seen that way, the running costs for a dehumidifier are usually worth paying, as long as you are not wasting energy by over-drying or running an undersized unit nonstop.

How Humidity Setpoint Changes the Bill

The humidistat setting has a bigger effect on cost than most people realize. Each step drier makes the compressor run longer, and the last few percentage points are the hardest to remove.

• Target 45 to 50 percent relative humidity for most basements and living spaces. That range discourages mold and dust mites without over-drying.
• Avoid setting 30 to 35 percent unless you have a specific reason. It can double run time and dry out wood trim and floors.
• Use a separate hygrometer to check the built-in sensor. Built-in readings can be off by 5 percent or more.
• Close doors and windows in the area being dried. An open basement window can bring in more humid air than the unit can remove.

Energy-Efficient Models and Features

Dehumidifiers that earn an energy efficiency certification remove more water per kWh than older or uncertified models, often around 15 to 30 percent better. The efficiency figure is listed as liters of water removed per kWh. Higher is better.

Features that help keep costs down:

• Accurate humidistat with auto shut-off. Stops the compressor once the target is reached.
• Auto-restart after power loss. Returns to your setting without running at a default that may be drier than you want.
• Continuous drain or internal pump. A basement dehumidifier with pump can push water up to a sink or out a window, so the unit never stops when the bucket fills. That does not reduce energy per pint, but it lets you place the unit for best airflow and avoid emptying a bucket twice a day.
• Low-temperature operation. Units rated for cooler basements (down to about 41°F to 50°F) handle frost on the coil better and run more efficiently in cold spaces.

Ways to Lower Dehumidifier Running Costs

• Fix moisture sources first. Extend downspouts 4 to 6 feet from the foundation, regrade soil so it slopes away, and repair leaky plumbing.
• Seal the space. Weatherstrip basement doors, seal rim joists and cover sump pits with a sealed lid.
• Clean the filter monthly. A clogged filter restricts airflow and lengthens run time.
• Keep the coils clean. Dust buildup on the coil reduces efficiency.
• Size correctly. An undersized unit runs constantly and never reaches the target. A properly sized one cycles off.
• Give it room. Keep 6 to 12 inches of clearance around the intake and exhaust.
• Run the AC in summer. Central air also removes moisture, so a dehumidifier upstairs may be unnecessary while AC is running.

For an accurate reading of what your unit uses, plug it into a plug-in electricity usage monitor for a week. That captures real compressor run time in your conditions.

Safety and Placement

Plug a dehumidifier directly into a grounded wall outlet rather than an extension cord. Basement outlets should have GFCI protection, since basements are damp locations. Keep the unit on a level surface so the bucket float and drain work properly, and keep drain hoses free of kinks. Unplug the unit before cleaning the filter or coils.

When to Call a Pro

If a dehumidifier runs constantly and the space still stays over 60 percent humidity, the moisture problem is bigger than the appliance. Standing water, efflorescence on block walls, active leaks or visible mold point to drainage or foundation issues. A waterproofing contractor can evaluate grading, drainage and wall sealing, and a mold remediation professional should handle growth larger than about 10 sq ft. If the unit trips a GFCI repeatedly, have a licensed electrician check the circuit.