Dehumidifier Electricity Cost Calculator

Related Calculators

Table of contents

• How to use
• Common mistakes
• Definitions
• Methodology
• Limitations & assumptions
• Sources

Watt: A measure of how fast the dehumidifier uses electric power at a moment in time.

kWh: Kilowatt-hour. This is the amount of electricity used when 1,000 watts runs for 1 hour.

Electricity rate ($ per kWh): The price you pay for each kWh. Your full bill rate may include supply, delivery, and other per-kWh charges.

Actual full-power running time (percent): The share of the scheduled time when the dehumidifier is really running at its rated power.

Standby power: Small electric draw when the dehumidifier is not scheduled to run, such as a display or control board.

Average power across a full day: The day's total electricity use spread evenly over 24 hours.

Mistake: Using amps in Dehumidifier power (watts) .
Fix: Enter watts, or estimate watts as volts times amps if the label only lists amps.

Mistake: Entering only compressor-on time in Time plugged in and set to run (hours per day) while also lowering Actual full-power running time (percent) .
Fix: Put the scheduled plugged-in time in hours, then use the percent field for cycling.

Mistake: Leaving Electricity rate ($ per kWh) as a guess when your bill has a different rate.
Fix: Use the total price per kWh from your electric bill for the best estimate.

Mistake: Putting a yearly day count in Days used in the bill period (days) and also using Months used per year (months) .
Fix: Enter days in one typical active bill period or month, then enter the number of active months.

Mistake: Treating Estimated savings from cycling as a utility rebate or guaranteed savings.
Fix: Use it as a comparison with 100 percent full-power use for the same scheduled hours.

• The estimate uses rated watts. Real wattage can change with fan speed, room temperature, humidity, frost control, and model design.
• The cycling setting is an average. A humidistat may run more on wet days and less after the room dries out.
• Yearly results treat Days used in the bill period (days) as the days in a typical active month, then multiply by Months used per year (months).
• The calculator does not model bucket shutoff, drain problems, dirty filters, defrost cycles, or changes in basement moisture over time.
• The default Electricity rate ($ per kWh) is only a starting value. Your utility rate is the better input.
• Standby use is counted only outside the scheduled run time, so Time plugged in and set to run (hours per day) cannot add standby hours beyond 24 hours.

Calculation steps

The calculator first converts watts to kilowatts by dividing by 1,000. It then multiplies by scheduled hours, the full-power running percent, and the number of days. If standby watts are entered, standby use is added for the part of the day outside the scheduled run time.

daily_kwh = (watts / 1000) * hours_per_day * (running_percent / 100) + (standby_watts / 1000) * (24 - hours_per_day)

period_kwh = daily_kwh * days_per_period

period_cost = period_kwh * electricity_rate

daily_cost = daily_kwh * electricity_rate

yearly_kwh = daily_kwh * days_per_period * months_per_year

yearly_cost = yearly_kwh * electricity_rate

average_watts = (daily_kwh / 24) * 1000

cycling_savings_period = (((watts / 1000) * hours_per_day * (1 - running_percent / 100)) * days_per_period) * electricity_rate

Worked example

For a 500 watt dehumidifier set to run 8 hours per day for 30 days at $0.18 per kWh, with 100 percent full-power running time and 0 standby watts, daily use is 4.00 kWh. The bill-period use is 120.00 kWh, so the estimated bill-period cost is $21.60. If the same pattern is used for 12 active months, the yearly estimate is 1,440.00 kWh and $259.20.

Calculation choices

Estimated savings from cycling appears only when Actual full-power running time (percent) is below 100. It compares the selected cycling percent with full-power use for the same scheduled hours. It does not treat standby watts as a savings item.