How Much Electricity Does a Dehumidifier Use?

What determines a dehumidifier's electricity use

A dehumidifier converts electrical energy into fan motion and compressor work to pull moisture from the air. The amount of electricity it uses over a day depends on three things: the wattage the components draw, the number of hours the unit actually runs, and how efficiently it turns that electricity into water removal. The first two are largely under your control; the third is a design characteristic of the model you choose.

You can think of a dehumidifier as a motor-driven appliance. It has an air-circulating fan and a refrigerated surface that condenses moisture, as described by the U.S. Department of Energy in its definition of a dehumidifier. When the compressor and fan are active, the unit draws current from the wall; when the humidistat is satisfied, the compressor cycles off and the draw drops. The total energy use is therefore the product of the wattage during operation and the total run time, plus small amounts for standby and control electronics.

Run time is never constant. It changes with the relative humidity in the space, the air temperature, and how the dehumidifier's capacity compares to the moisture load. That is why two identical-looking units can have very different monthly energy use in different homes. To estimate your own usage, you need to know the unit's ratings and its typical cycle pattern. The rest of this article walks through each factor. To review the basics of how these machines work, see how a dehumidifier works.

Wattage and amps on the label

Every residential dehumidifier carries a nameplate that lists electrical ratings: voltage, amperage, and wattage or a kilowatt rating. Wattage is the rate at which the unit consumes electrical power. Amperage, or current, is the flow of electrons. On a standard household circuit, a dehumidifier's amperage tells you how much of the circuit's capacity it uses. If you plan to run other appliances on the same circuit, the sum of their amps must stay below the breaker rating.

The U.S. Department of Energy defines a dehumidifier as a self-contained, electrically operated assembly. That means the electrical components are enclosed and the unit plugs into a normal outlet. Most portable units are rated for 120 volts. Whole-home units may require different wiring. You can find the exact ratings on the nameplate or in the product manual. For guidance on what the electrical specifications mean for your home, see dehumidifier electrical requirements.

What makes a dehumidifier run longer

The single biggest factor in run time is the relative humidity you're trying to maintain. The CDC recommends keeping indoor humidity at or below 50% to prevent mold growth. If your space is currently soaked and you set the humidistat to 45%, the unit will run more than if you set it to 55%. The difference can add or remove hours of operation each day. See recommended humidity settings for guidance.

Air temperature also matters. The DOE test procedure for portable dehumidifiers runs them at 65°F, which reflects a typical basement. Colder air holds less moisture, so the unit removes less water and may need to run longer to reach the same humidity level. If the temperature drops below 65°F, frost can form on the coils, causing the compressor to cycle on and off. The ENERGY STAR buying guidance notes that this reduces performance. Some models have anti-frost sensors that shut the unit off automatically.

Finally, sizing plays a role. A dehumidifier that is too small for the space will run almost continuously to keep up, while an oversized unit will cycle on and off more often. The ENERGY STAR capacity tables provide recommended pint ranges for different room sizes and dampness levels. Oversizing is generally better than undersizing, as the ENERGY STAR site says. See sizing a dehumidifier by square feet to match capacity to your space.

How efficiency is measured: IEF and liters per kWh

To compare energy use across models, the U.S. Department of Energy established a metric called the Integrated Energy Factor (IEF), expressed in liters of water removed per kilowatt-hour of electricity consumed. A higher IEF means the unit removes more water for each unit of energy. The DOE standard, effective since June 2019, includes the energy the unit uses when it cycles off, not just when the compressor runs. For an in-depth explanation, see integrated energy factor explained.

ENERGY STAR certified dehumidifiers use more efficient refrigeration coils, compressors, and fans. According to the ENERGY STAR program, they remove the same amount of moisture as a similarly sized conventional unit while using about 20% less energy. If you are choosing between models, look for the ENERGY STAR label. You can also compare the IEF values listed on the product labels. The DOE sets minimum efficiency levels for different capacity categories, so a higher IEF generally means a more efficient unit.

How to estimate your own electricity use

You don't need to monitor the unit for weeks to get a rough estimate. Start with the wattage printed on the nameplate. Then estimate the number of hours per day the compressor actually runs, which is shorter than the time the unit is plugged in. Multiply the two and divide by 1,000 to get kilowatt-hours per day. That daily figure, multiplied by your local electricity rate, gives an approximate cost, but for comparing dehumidifiers you only need the kilowatt-hours. The hourly operating load is not constant; it changes as the humidistat cycles the compressor.

An alternative approach uses the IEF. If you know how many liters of water the unit removes in a day, you can divide that by the IEF to get kilowatt-hours. The exact conversion depends on the units you use, but the concept is straightforward: a more efficient unit uses less energy for the same water removal. See energy efficiency IEF explained for the details.

Choose an efficient model and run it smartly

The simplest way to limit electricity use is to buy a model that carries the ENERGY STAR label. These units use about 20% less energy than comparable conventional models, according to the ENERGY STAR program. They are available in both portable and whole-home configurations. To compare current models, browse our best ENERGY STAR dehumidifiers guide.

Once you own a unit, run it according to the manufacturer's guidelines. Set the humidistat to a value that keeps mold from forming, typically 50% or lower as recommended by the CDC. Keep the air filter clean so air flows freely, and place the unit where it can draw air from the whole space. For basements, a unit with a pump and continuous drain may run more efficiently because you don't have to empty the bucket. See our best basement dehumidifiers guide for suggestions.

If you have a large area or persistent dampness, consider a whole-home unit that ducts into your HVAC system. These are installed permanently and may have different run patterns. The choice between portable and whole-home depends on your space and needs; read portable vs whole-house dehumidifiers to decide.

What to pick for your use

Questions

How many watts does a dehumidifier use?

The wattage is listed on the nameplate and varies by model and capacity. Portable units typically draw less than whole-home units, but the exact figure depends on the compressor and fan. You can find it in the product documentation, then use it to calculate daily kilowatt-hours.

How many amps does a dehumidifier draw?

Amperage is also on the nameplate. For a standard 120-volt outlet, the current draw is usually below 10 amps for most portable units. You should check the label to ensure the circuit isn't overloaded, especially if you run other appliances on the same breaker.

Does a dehumidifier use more electricity when it's humid?

Yes. Higher humidity forces the compressor to run longer to reach the set point, which increases run time and therefore energy use. The difference can be significant between a damp basement and a moderately humid living room.

How do I calculate the cost of running a dehumidifier?

Multiply the kilowatt-hours per day by your electricity rate. To get kilowatt-hours, multiply the wattage by the daily run hours and divide by 1,000. Local rates vary, so check your utility bill for the per-kWh charge.

Is an ENERGY STAR dehumidifier worth it?

ENERGY STAR certified models use about 20% less energy than comparable conventional units, per the EPA program. Over the life of the appliance, that can translate into noticeable savings without sacrificing moisture removal.