How much electricity does a dehumidifier use?
A certified portable dehumidifier uses 335 kWh a year. That is the median of 530 certified models, and the middle half fall between 276 and 507. At the US average tariff that is about $61 a year.
Every page answering this question answers it in watts - 300 to 700, or 500, or 20 for a small one. Those figures are not wrong, but they are not the answer either: watts are what the machine draws while the compressor runs, and your bill is in kilowatt-hours. Everything between the two is an assumption about hours, and for this appliance the assumption is published as a number.
- How much electricity does a dehumidifier use per year?
- 335 kWh a year, on the federal test procedure's assumptions about how much the appliance is used. At 18.34¢ per kWh that is about $61.44 a year.
- How much electricity does a dehumidifier use per month?
- About 28 kWh a month, which is the yearly figure divided by twelve. There is no separate monthly measurement: the certification tests a year of defined use.
- How much electricity does a dehumidifier use per day?
- About 0.92 kWh a day, the yearly figure spread over 365 days. It is not the nameplate wattage multiplied by 24: an appliance certified this way draws its rated power only part of the time, and multiplying by 24 hours overstates the real figure several times over.
Work it out with your own tariff
Residential sector, US average, as published in Electric Power Monthly released 26 August 2026. This is a revenue-weighted average across all residential customers and utilities, not a tariff any single household pays. In the same month the state residential averages (table 5.6.A) ran from 14.37 cents in Idaho to 52.72 in Hawaii, with California at 34.74 and New York at 29.49 — a spread of more than three and a half times. Use the figure from your own bill; the default here is a placeholder, not an answer.
Your rate, cents per kWh
There is no hours setting here, unlike the other device pages. This appliance is not certified in watts at all — only as a yearly total, and that total already includes a defined pattern of use. Multiplying it by hours of your own would count the usage twice.
| Period | Cost | Where it comes from |
|---|---|---|
| A year | $61 | 335 kWh — the measured figure |
| A month | $5.12 | a twelfth of the year |
| A day | $0.17 | a 365th of the year |
335 kWh × 18.34¢ = $61 a year. That averages 38 W drawn continuously.
335 kWh a year is the median of 530 certified portable dehumidifiers; the middle half fall between 276 and 507. The figure is the Integrated Annual Energy Consumption reported under ENERGY STAR Version 6.0, which fixes dehumidification-mode operation at 1,095 hours a year - three hours a day - and adds a year of low-power mode to it. Watts are not published for this appliance at all. Rate defaults to 18.34¢ (U.S. Energy Information Administration, June 2026) — a national average, which is wrong for you specifically, so put your own in above.
The published figure assumes three hours a day
Every appliance page has an assumption buried in it somewhere. This is the one appliance where the assumption is printed as a number, in the specification itself:
IAEC = E_TLP + E_DM x (1095 / 2)
where 1,095 is "the number of annual hours in dehumidification mode" and 2 is the length of the test in hours. The same constant appears in the federal test procedure, which spells out what it is for: converting a two-hour measurement into a year.
1,095 hours divided by 365 days is exactly three hours a day.
So the annual figure is not "a dehumidifier running in your basement". It is three hours a day of dehumidifying, plus a year of standby. If yours runs longer, the larger part of the figure scales with it:
| If it dehumidifies | Hours a year | Against the label |
|---|---|---|
| 3 hours a day | 1,095 | the published figure |
| 6 hours a day | 2,190 | 2x |
| 8 hours a day | 2,920 | 2.7x |
| 12 hours a day | 4,380 | 4x |
| Continuously | 8,760 | 8x |
That multiplier applies to the dehumidification term, not to the whole number: the standby term is a fixed annual amount and does not grow with use. It is the smaller of the two, but the certified data publishes only the total, so the split cannot be recovered from it. Read the multipliers as close to the whole figure rather than exactly it.
The year in the test procedure is not a whole year
The same section of the test procedure fixes two more constants: 1,840.5 hours in inactive or off mode and 1,840.5 hours in off-cycle mode, the state where the machine is running but the compressor is not.
Those three numbers add to 4,776 hours - about 199 days. The remaining 3,984 hours of the year are not in the calculation at all. The model is a dehumidifying season, not a calendar year, and this is worth knowing before comparing the figure with a January-to-December line on your bill.
By capacity
| Capacity (pints/day) | Middle half | Median | Models |
|---|---|---|---|
| Up to 25.00 | 183-285 kWh | 276 kWh | 261 |
| 25.01 to 35.00 | 336-343 kWh | 341 kWh | 38 |
| 35.01 to 45.00 | 369-383 kWh | 378 kWh | 65 |
| 45.01 to 50.00 | 512-526 kWh | 520 kWh | 166 |
The 25.00 and 50.00 lines are the specification's own; the two in between are drawn here for readability. Notice how tight the middle three bands are - a few kilowatt-hours wide - and how wide the smallest one is. Small units include everything from a 1-pint tabletop box to a proper 25-pint machine, and averaging across them is close to meaningless.
Nothing certified removes more than 50 pints a day
Of 530 certified portable models, the largest is rated at exactly 50.00 pints a day. Not one is above it. And 166 of them - roughly a third of the entire certified market - sit in the last five pints below the line, with 134 of those in the final pint.
The specification explains where the line comes from:
| Capacity (pints/day) | Integrated energy factor required |
|---|---|
| Up to 25.00 | 1.70 L/kWh |
| 25.01 to 50.00 | 2.01 L/kWh |
| 50.01 and above | 3.30 L/kWh |
Crossing 50.00 pints raises the efficiency requirement by 64% in a single step. What the data shows is where models sit and what the rule requires; that manufacturers rate to just under the line is the obvious reading of the two together, not something either one proves on its own.
Practically, though, the ceiling is real: if you are shopping for a certified portable dehumidifier bigger than 50 pints a day, there is nothing to buy.
Two official pages disagree about the boundary
The specification PDF gives the third band as "50.01 and above". The key criteria page on the same site gives it as "50", which would put a machine rated exactly 50.00 into two bands at once, requiring 2.01 and 3.30 of it simultaneously. Thirty-two certified models are rated at exactly 50.00, and their efficiency sits around 2.02 - so the specification is the one being applied.
Checked on 9 September 2026. It is a small thing, but it is the reason this page quotes the specification rather than the summary page.
Ducted whole-home units are a different appliance
Twenty-four certified models are whole-home units, ducted into the return air. Their median is 628 kWh a year, with the middle half between 556 and 1,023 - roughly twice a portable.
They are not certified on the same basis. Portables are graded on pints per day; whole-home units are graded on the volume of the case. And the capacities are not comparable even as numbers, because the test conditions differ: portables are measured at 65 degrees Fahrenheit and 60% relative humidity, whole-home units at 73 degrees. A dehumidifier removes less water from colder air, so the same machine would be rated differently under the two tests.
Per month
335 kWh over twelve months is about 28 kWh a month, roughly $5 - but as with the season above, that is a twelfth of an annual figure rather than a month of use. In the humid months when it actually runs, it is more; in February, for most homes, it is nothing.
What it costs you specifically
Set your own tariff below.
What this does not account for
Three hours a day is the largest source of error here. A dehumidifier in a damp basement in July runs most of the day, and the dehumidification part of this figure would be four to eight times larger. Unlike the cooling season on the air conditioner page, this assumption is published as a number, so you can adjust for it - which is why the multipliers are on the page.
Certified models are a biased sample. Certification is voluntary and efficient models earn it. An uncertified or older machine uses more, and there is no certified data describing it.
Capacity is measured at 65 degrees, not at room temperature. A machine rated 50 pints a day removes that much in the test conditions. In a colder crawl space it removes less and runs longer; in a warm humid room it can remove more.
The two dehumidifier families are not comparable. Portable and whole-home units are tested at different temperatures and certified against different measures. Comparing their pint ratings, or their annual figures, compares two different tests.
Worth reading next
Sources
- 01ENERGY STAR certified dehumidifiers — reported integrated annual energy consumptionU.S. Environmental Protection Agency ·
- 02Electric Power Monthly, Table 5.3 — average price of electricity to ultimate customersU.S. Energy Information Administration ·
How these figures are produced: see our methodology.
Figures are calculated from published wattages and a published tariff, both dated above. They are good for comparing devices, not for predicting your bill: your rate, settings and usage all differ.