How much does a dehumidifier cost to run?

The formula

Energy in kWh is watts times hours divided by 1,000. A 200 W dehumidifier running for 5 hours uses 1 kWh. Multiply by your unit rate in pence per kWh to get the cost. Our running-cost calculator does this for up to three appliances side by side.

Use the rated power input, not the maximum. Makers often list a rated power and sometimes a maximum. Some models also list different figures for each fan speed or mode. Desiccant models often have a lower and higher heat setting with very different wattages.

Compressor models in kWh

Compressor dehumidifiers for homes typically draw somewhere around 150 to 300 W on 10 to 20 litre models, with some low energy models below that and larger models above it. These figures assume the compressor runs the whole time, as in continuous mode or laundry mode.

Desiccant models in kWh

Desiccant dehumidifiers use a heater to dry their zeolite wheel, so they draw more power, often around 300 to 650 W depending on model and setting. Many have an economy or low setting that roughly halves the wattage.

Why real use is often lower

With a humidity target set, the machine stops extracting once the room reaches it. The fan may keep running at low power, but the compressor or heater switches off. In a home where the target is reached quickly, the machine might extract for only part of each hour. So the tables above are an upper figure for continuous running, not a typical day.

Setting the target too low keeps the machine running longer. Most homes do well at around 50 to 60 % RH. Our guide to dehumidifier humidity settings explains why going lower costs more for little gain, and how long to run a dehumidifier covers running hours.

Which type is cheaper to run?

In a warm room, a compressor model usually collects more water per kWh, because the cold coil works well and the wattage is lower. In a cold room below about 15 °C the balance shifts. The compressor model's output falls and it spends time defrosting, while the desiccant model keeps extracting steadily. In a cold garage the desiccant unit can collect more water per kWh, even with its higher wattage.

So the cheapest machine to run is the one matched to the room. Compare stated watts per litre for similar conditions. Our guide to the best low energy dehumidifiers ranks models on stated watts, and desiccant vs compressor explains the choice.

See the best low energy dehumidifiers →

Ways to cut kWh

Most savings come from running fewer hours rather than picking a slightly lower wattage.

• Set a sensible target of around 50 to 60 % rather than continuous
• Close doors and windows in the room being dried
• Clean the filter so airflow stays strong
• Use a timer or a laundry mode that switches off
• Pick a compressor model for heated rooms and desiccant for cold ones
• Size the machine so it reaches the target quickly

Frequently asked questions

How much electricity does a dehumidifier use? A compressor model typically draws around 150 to 300 W, so 0.15 to 0.3 kWh per hour of running. Desiccant models draw more, often 300 to 650 W.

Are dehumidifiers expensive to run? Compressor models use similar power to a few old style light bulbs. Running costs depend mainly on hours. Work out kWh and multiply by your unit rate.

Is it cheaper to run a dehumidifier or a tumble dryer? A dehumidifier draws fewer watts but runs longer. Compare kWh per load, using the dryer's energy label and the dehumidifier's watts times hours.

Does a dehumidifier use electricity on standby? A little, to power the display and sensor. It is small compared with running, and the manual or listing may give a standby figure.