How Much Does It Cost to Run a Dehumidifier All Day?
Intro
Dehumidifiers are often used for long periods of time, especially in basements, damp rooms, or during humid seasons. Because they can run frequently, many people wonder how much electricity they actually use and whether the cost adds up. In this article, we’ll explain how dehumidifier electricity costs are calculated, show realistic cost examples, and clarify what “running all day” actually means in real-world use.
What affects the cost of running a dehumidifier
The cost of running a dehumidifier depends on a few straightforward factors.
Power usage
Most residential dehumidifiers use between 300 and 700 watts, depending on their size, capacity, and efficiency.
Electricity rate
Electricity is billed per kilowatt-hour (kWh). Rates commonly range from $0.15 to $0.30 per kWh, depending on location and utility provider.
Actual run time
Dehumidifiers do not usually run nonstop. They cycle on and off based on humidity levels or shut off automatically when a collection tank fills.
How dehumidifier electricity cost is calculated
The basic calculation looks like this:
Wattage ÷ 1,000 × hours running × electricity rate = cost
This formula can be used to estimate daily, weekly, or monthly costs once you know how often the unit actually runs.
Do dehumidifiers really run all day?
In most homes, dehumidifiers do not run continuously.
If a unit relies on a collection tank, it will shut off automatically once the tank fills and won’t run again until it’s emptied. In those cases, true 24-hour operation isn’t possible, and actual run time is often much lower.
When a dehumidifier does run all day, it usually means the unit is connected to a continuous drain hose. With a drain in place, water exits automatically, allowing the dehumidifier to cycle on and off based only on humidity levels rather than tank capacity.
When a tank fills quickly, the dehumidifier actually spends less time running, which reduces electricity usage. However, this also means the unit is no longer removing moisture once it shuts off. In other words, a lower electricity cost in this situation often comes from reduced operation, not improved performance.
Because of this, 24-hour cost examples should be viewed as upper-bound or maximum scenarios, not typical daily usage.
Real-world cost examples
Running a 500-watt dehumidifier for about 8 hours per day
0.5 kWh × 8 hours = 4 kWh
4 kWh × $0.20 = $0.80 per day
That works out to about $24 per month if used daily.
Running a 500-watt dehumidifier with a drain for up to 24 hours
0.5 kWh × 24 hours = 12 kWh
12 kWh × $0.20 = $2.40 per day
That comes out to roughly $72 per month.
This represents a worst-case or maximum cost, assuming the unit is connected to a drain and allowed to operate continuously.
Smaller or more efficient units
Smaller or more energy-efficient dehumidifiers typically use less electricity, but their actual cost still depends on how long they run each day.
A smaller 300-watt dehumidifier uses about 0.3 kilowatt-hours per hour when it is actively running.
Running a 300-watt dehumidifier for about 8 hours per day
0.3 kWh × 8 hours = 2.4 kWh
2.4 kWh × $0.20 = $0.48 per day
That works out to roughly $14 to $15 per month if used daily.
Running a 300-watt dehumidifier with a drain for up to 24 hours
0.3 kWh × 24 hours = 7.2 kWh
7.2 kWh × $0.20 = $1.44 per day
That comes out to around $43 per month at the same electricity rate.
This represents an upper-bound scenario, assuming the unit is allowed to run continuously and is connected to a drain.
In practice, many smaller dehumidifiers cycle on and off frequently, especially in moderately humid spaces. When this happens, actual run time is often closer to the lower end of these examples, which keeps electricity costs down. However, shorter run times can also mean slower moisture removal, depending on the conditions in the space.
When dehumidifier costs can add up
Dehumidifier costs are more noticeable when:
The unit is connected to a drain and runs frequently
Humidity levels remain consistently high
Electricity rates are higher than average
Multiple dehumidifiers are used
In these situations, monthly electricity costs can become more noticeable over time.
When the cost is usually modest
The cost is often reasonable when:
The unit cycles on and off regularly
It’s used seasonally rather than year-round
The space is reasonably sealed
Humidity drops quickly once the unit runs
For many homes, the electricity cost is relatively small compared to the benefits of moisture control.
How to estimate your own dehumidifier’s cost
To estimate your own cost:
Check the wattage listed on the dehumidifier
Look up your electricity rate on your utility bill
Estimate how many hours per day the unit actually runs
Some dehumidifiers also display energy usage directly, which can make tracking easier.
The bottom line
Dehumidifiers don’t use as much electricity as major appliances, but frequent operation can still add up over time. Actual cost depends on wattage, humidity levels, run time, and whether the unit is connected to a drain. Understanding how cycling and shutoff affect performance makes it easier to estimate realistic costs instead of assuming constant 24-hour operation.