Quick answer: A household dehumidifier typically draws 300–700 W. Commercial and industrial refrigerant dehumidifiers draw from under 1 kW for a 60 L/day portable unit to about 15 kW for a 960 L/day floor-standing unit. Daily energy is power × running hours, and running hours depend on how wet the space is. The fairer way to compare machines is litres of water removed per kWh at the same test condition.
Quick answer
- kWh per day = power (kW) × hours the compressor runs.
- Cost per day = kWh × your electricity price.
- Efficiency = litres removed ÷ kWh used, compared at the same temperature and humidity.
How much power does a dehumidifier use?
| Type | Typical capacity | Typical power draw |
|---|---|---|
| Small home unit | 10–20 L/day | about 200–400 W |
| Large home or basement unit | 20–50 L/day | about 400–700 W |
| Commercial portable | 60–140 L/day | about 0.8–1.7 kW |
| Industrial floor-standing or ceiling | 170–960 L/day | about 3–15 kW |
The power draw of an industrial unit is set mainly by its compressor and fans. Here are the published figures for our ranges, with capacity rated at 30 °C/80 % RH:
| Model | Rated removal (30 °C/80 % RH) | Airflow | Maximum power | Supply |
|---|---|---|---|---|
| RYCM-60C portable | 60 L/day | 480 m³/h | 0.78 kW | 220 V, 1-phase |
| RYCM-90C portable | 90 L/day | 1,000 m³/h | 1.35 kW | 220 V, 1-phase |
| RYCM-138C portable | 138 L/day | 1,300 m³/h | 1.68 kW | 220 V, 1-phase |
| RYCF-10S floor-standing | 240 L/day | 2,800 m³/h | 4.25 kW | 380 V, 3-phase |
| RYCF-22S floor-standing | 480 L/day | 5,600 m³/h | 8.4 kW | 380 V, 3-phase |
| RYCF-40S floor-standing | 960 L/day | 10,000 m³/h | 15 kW | 380 V, 3-phase |
Full specifications are on the industrial dehumidifier and ceiling-mounted dehumidifier pages.
How do you calculate daily kWh and cost?
Use the power the unit actually draws and the hours its compressor runs.
kWh per day = power (kW) × running hours Cost per day = kWh per day × electricity price
Example: an RYCF-10S running 12 hours a day at no more than its 4.25 kW maximum uses up to 51 kWh. At $0.12 per kWh that is up to $6.12 a day, or about $184 over 30 days. Real use is usually lower, because the compressor stops once the room reaches its humidity setpoint and the unit draws less than its maximum power at most conditions.
For the most accurate figure, fit a kWh meter on the unit's supply for a week and read the total. A whole-building meter cannot separate the dehumidifier from other loads.
How do you compare dehumidifier efficiency?
Divide water removed by electricity used. The result, in litres per kWh, tells you how much water each unit of electricity removes. Residential units in the US are rated this way as the Integrated Energy Factor (IEF), and ENERGY STAR certified models are about 20 % more efficient than standard ones (ENERGY STAR).
Two rules make the comparison fair:
- Same condition. A unit tested at 30 °C/80 % RH removes far more water per kWh than the same unit tested at 18 °C/60 % RH. Compare like with like.
- Same power basis. Use rated running power at the test condition, not the maximum power on the nameplate.
As a lower bound, dividing our rated removal by maximum power gives at least 2.3–3.4 L/kWh at 30 °C/80 % RH across the RYCM and RYCF ranges. Ask us for the running power at your condition for a precise figure.
What makes a dehumidifier use more electricity?
- More running hours. A wet space, a low setpoint, open doors or high ventilation keep the compressor on longer. Seal openings and set the humidity target you actually need.
- Cool air. Below about 18 °C, coils can ice and the unit spends time defrosting. A low-temperature model or a desiccant dehumidifier is more efficient in cold spaces.
- Dirty filters and coils. Restricted airflow cuts water removal per kWh. Clean filters on a schedule.
- Wrong size. An undersized unit runs continuously without reaching the target; a heavily oversized one cycles on and off. Size from the moisture load, not the floor area alone. See our dehumidifier sizing guide.
Does a dehumidifier heat the room?
Yes. Almost all the electricity it uses, plus the heat released when water vapor condenses, ends up as heat in the room. In a greenhouse or cold store in winter this heat is useful; in a warm warehouse in summer it adds to the cooling load. Account for it when you compare running costs with ventilation or heating.
For greenhouses, record dehumidifier electricity and heating fuel separately, so you can see whether the heat from the dehumidifier reduces your fuel use.
How to cut running cost
- Set the highest humidity target that still protects the product or process.
- Close doors and reduce uncontrolled outdoor air.
- Clean filters and check drainage monthly.
- Run on a humidistat, not continuously.
- Choose the technology for the temperature: refrigerant units above about 15–18 °C, desiccant units for cold or very dry targets.
FAQ
Frequently asked questions
How many watts does a dehumidifier use?
Home units about 300–700 W. Commercial portable units about 0.8–1.7 kW. Industrial units up to about 15 kW.
Does a dehumidifier use a lot of electricity?
A home unit uses about as much as a small space heater while it runs. An industrial unit uses more, but it removes hundreds of litres a day. Compare cost per litre removed, not watts alone.
Is it cheaper to run a dehumidifier or an air conditioner?
For drying, a dehumidifier is usually cheaper, because it removes moisture without cooling the space. An air conditioner dries the air only as a side effect of cooling.
How much does it cost to run a dehumidifier 24 hours a day?
Multiply the unit's running power in kW by 24 and by your electricity price. A 0.5 kW home unit at $0.15/kWh costs up to $1.80 a day; a 4.25 kW industrial unit at $0.12/kWh up to about $12.20.
References
- ENERGY STAR, Dehumidifiers: efficiency and capacity information.
- US Energy Information Administration, Electricity explained: measuring electricity.
- US Department of Energy, Energy conservation standards for dehumidifiers (Integrated Energy Factor).
