How Many Watts Does a Dehumidifier Use? By Size, With kWh and Cost

A dehumidifier is a small refrigeration system with a fan. Air passes over a cold coil, water condenses into the bucket or a drain, and the air is warmed back up on the way out. The compressor is what uses the power, and how much it uses tracks the unit's size and efficiency.

Running watts from the ENERGY STAR ratings

Manufacturers don't always print running watts on the box, but the ENERGY STAR certified list gives two numbers that get you close:

• Water removal capacity, in pints per day.
• Integrated energy factor (IEF), in liters of water removed per kWh. ENERGY STAR describes a higher IEF as a more efficient dehumidifier.

Convert pints to liters (one pint is about 0.473 liters), divide by the IEF to get kWh per day of continuous running, then divide by 24 for kilowatts. The IEF also counts fan-only and standby energy, so treat the result as an estimate of running watts, not a nameplate figure.

These models are from the ENERGY STAR certified dehumidifiers list, read in October 2026:

Capacity, IEF and annual kWh are the certified ratings. The watts are arithmetic from them, rounded.

Across the list, the median estimate is about 258 watts for portable models under 25 pints, about 344 watts for 25 to 40 pints and about 488 watts for 40 to 60 pints. The rated annual energy on the list works out to roughly 1,100 hours of running at those watts, which is a rating assumption, not a promise about your basement.

Bigger units are more efficient per pint

The smaller portable models in the table are rated at an IEF of 1.70, the 35- and 50-pint models at 2.01 and the Aprilaire whole-home units at 2.35. A larger unit draws more watts while it runs, but it removes more water per kWh, so it may reach the humidity setting and cycle off sooner.

ENERGY STAR's sizing chart starts at 20 to 30 pints a day for a slightly to moderately damp small-medium room (50 to 75 percent relative humidity) and goes to 50+ pints for a wet, large space. It notes that it is better to oversize than undersize.

Amps and the circuit

Divide watts by volts for amps. At 120 volts:

• about 258 W is roughly 2.2 amps
• about 352 W is roughly 2.9 amps
• about 490 W is roughly 4.1 amps

The rating plate shows the maximum to use for circuit planning, which can be higher than running draw. A dehumidifier sharing a basement circuit with a freezer, a sump pump or a laundry load is worth checking before you add one. The watts to amps calculator does the conversion at any voltage.

kWh per day and running cost

Running watts × hours the compressor runs ÷ 1,000 = kWh. A dehumidifier with a built-in humidistat (every ENERGY STAR model has one) cycles off when the room reaches its setting, so the hours depend on how damp the space is:

• 490 W for 8 hours: about 3.9 kWh
• 490 W for 24 hours: about 11.8 kWh
• 258 W for 8 hours: about 2.1 kWh

For a yearly figure, the rated annual kWh times your rate is the simplest illustration. At 16 cents per kWh:

• 276 kWh a year (22-pint Midea): about $44
• 379 kWh a year (35-pint Frigidaire): about $61
• 516 kWh a year (50-pint Honeywell): about $83

Your bill's rate and your humidity change those numbers. The watts to kWh calculator runs your own.

ENERGY STAR says certified dehumidifiers use about 20 percent less energy than conventional units removing the same moisture. It also suggests cutting the moisture at the source: extend downspouts, slope soil away from the foundation, vent the dryer outdoors and use bath and kitchen fans. It puts the optimum indoor relative humidity at 30 to 50 percent.

A dehumidifier on battery backup

In an outage, a dehumidifier is a load you choose, not one you need.

• Energy adds up. About 490 watts for 8 hours is roughly 3.9 kWh, a meaningful share of a home battery's stored energy.
• The sump pump comes first. In a damp basement, the sump pump is the load that keeps water out. The dehumidifier can come back on once the grid does.
• It has to be on the right circuit. A basement unit is often on a different circuit from the kitchen. If that circuit isn't on the critical load panel, the dehumidifier is off in an outage.

The critical load panel planner checks whether a battery can carry the circuits you choose. Sump pumps, refrigerators and freezers are the usual first picks on the home battery and backup projects Seamless Home coordinates. Get a free estimate to start. Coverage is confirmed per service area rather than promised as blanket availability.