What a Dehumidifier Costs to Run, and How to Cut It

What does a dehumidifier cost to run? A typical portable basement dehumidifier draws about 300 to 700 watts while it runs. In a damp Canadian basement over the summer, that usually works out to roughly $5 to $35 a month, depending on runtime and your electricity rate. A unit that runs around the clock in a wet basement can cost more.

The biggest lever is runtime. A dehumidifier set to a sensible humidity level, in a basement where moisture sources are fixed, may run a few hours a day instead of all day.

How to estimate your dehumidifier's running cost

Multiply the wattage by hours of use, divide by 1,000 to get kWh, then multiply by your rate. A 500 W unit running 10 hours a day uses 5 kWh a day, or about 150 kWh a month. Check the label for wattage, or use a plug-in power meter for a real reading. The appliance calculator does the maths for you.

Typical monthly cost by province

The table assumes a 500 W unit running 10 hours a day, about 150 kWh a month. Rates are approximate all-in residential figures.

Halve the runtime and you halve the cost. Many basements need far less than 10 hours a day once the humidistat is set correctly.

Ways to cut dehumidifier costs

Set the right humidity level

Aim for about 45% to 50% relative humidity in the basement. Going lower uses a lot more energy for little benefit. Avoid continuous mode unless you have a specific moisture problem. A cheap hygrometer helps you confirm the built-in reading.

Fix moisture at the source

• Extend downspouts at least 1.5 to 2 metres from the foundation.
• Make sure soil slopes away from the house.
• Check that the dryer vents outside and the vent is not disconnected.
• Fix plumbing leaks and insulate cold water pipes that sweat.
• Run bathroom fans during and after showers.

Keep the space closed

Close basement windows in humid weather. Warm, moist outdoor air brings in more water than it removes. Air sealing the rim joists also reduces humid air coming in. See our air sealing guide.

Maintain the unit

• Clean the filter every few weeks.
• Keep it away from walls so air flows freely.
• Use a hose to a floor drain so a full bucket does not stop the unit and tempt you into resetting it to continuous.
• Run it in a space that stays above about 18 °C. Many units lose efficiency and frost up in cold rooms.

Choosing an efficient dehumidifier

ENERGY STAR certified dehumidifiers remove more water for each kWh of electricity. For a unit that runs most of the summer, that adds up over its life. Size matters too. A unit that is too small runs constantly, while a properly sized one reaches the setpoint and cycles off. Check the capacity rating against the size and dampness of your space.

Whole-home dehumidifiers that tie into ductwork cost more to install but can be more efficient for large or very damp basements.

Signs your basement has a bigger moisture problem

A dehumidifier treats the symptom. Watch for these signs that the cause needs attention:

• Water stains or white mineral deposits on foundation walls.
• A musty smell that returns soon after the unit cycles off.
• Puddles after heavy rain or snowmelt.
• Mould on stored boxes, drywall or carpet.

These usually point to drainage, grading or foundation issues. A contractor or home inspector can help find the source.

Other options that help

• Air conditioning and heat pumps remove moisture as they cool. If your main floor is cool and dry, the basement may need less help. See our summer cooling guide.
• A heat pump water heater in the basement cools and dehumidifies the air as it heats water. Our heat pump water heater guide explains the trade-offs.
• Turn it off in winter. Basement air is usually dry in cold weather, so most homes can unplug the dehumidifier from late fall to spring.

If your dehumidifier runs constantly and still cannot keep up, that usually points to a water problem rather than a dehumidifier problem. Fix drainage first. To see how it compares with your other loads, try the energy check-up or our guide on standby power.