How this calculator works
Dehumidifier efficiency is rated as the Integrated Energy Factor (IEF): liters of water removed per kilowatt-hour. At its rated capacity a 50-pint unit removes about 23.7 liters a day if it runs nonstop. The calculator scales that by the hours the compressor actually runs, divides by the IEF to get kWh, and multiplies by your electricity price.
ENERGY STAR (Version 6.0, from October 2025) requires at least 1.70 L/kWh for units up to 25 pints/day, 2.01 for 25–50 pints and 3.30 for 50 pints and up.
Assumptions and tips
- IEF is measured at standard test conditions (65°F, 60% humidity); a cold basement removes less water per kWh.
- A humidistat set to 45–50% cuts running hours.
Worked example
Using the default values in the calculator above:
| Input | Value |
|---|---|
| Rated capacity | 50 pints/day |
| Efficiency (IEF) | 0 L/kWh |
| Compressor hours per day | 12 h |
| Days per month | 30 |
| Electricity rate | 0.182 $/kWh |
| Result | Value |
|---|---|
| Cost per month | $32.13 |
| Cost per day | $1.07 |
| Energy per day | 5.89 kWh |
| Average power while running | 490 W |
| IEF used | 2.01 L/kWh |
| Water removed per day (at rated conditions) | 25 pints |
Step by step:
- Water at rated capacity = 50 pints × 0.4732 × (12 ÷ 24 h) = 11.83 L/day
- Energy = 11.83 L ÷ 2.01 L/kWh = 5.89 kWh/day
- Cost = 5.89 kWh × $0.182 × 30 days = $32.13/month
Monthly running cost at ENERGY STAR minimum efficiency
12 compressor hours a day, 30 days, 18.2¢/kWh — calculated with this tool.
| Capacity | Cost per month | Energy per day |
|---|---|---|
| 22 pints/day | $16.72 | 3.06 kWh |
| 35 pints/day | $22.49 | 4.12 kWh |
| 50 pints/day | $32.13 | 5.89 kWh |
| 70 pints/day | $27.40 | 5.02 kWh |
Common mistakes to avoid
- Setting the humidistat too low — 45–50% is enough to stop mold and saves running hours.
- Running a dehumidifier in a cold basement where an air conditioner or heater would remove moisture more cheaply.
Frequently asked questions
How much does it cost to run a 50-pint dehumidifier?
At the ENERGY STAR minimum for its size (2.01 L/kWh) and 12 hours a day, about 5.9 kWh a day — roughly $1.07 a day or $32 a month at 18.2¢/kWh.
How many watts does a dehumidifier use?
Typically a few hundred watts while the compressor runs; the exact figure depends on size and efficiency.
Does an ENERGY STAR dehumidifier save money?
Yes — for the same water removed it uses less electricity, and the savings grow the more hours it runs.
Sources
- ENERGY STAR: Dehumidifier key efficiency criteria (Version 6.0)
- U.S. EIA Short-Term Energy Outlook: electricity prices
Built and reviewed by Anirban Kundu, Creator & Editor · M.Sc Physics, 20 years teaching science