How much does it cost to run a dehumidifier

Every answer to this question is one arithmetic line: hours, times watts, times the price of a kilowatt-hour. Two of those three are published. The middle one is not, and the federal efficiency standard is the closest thing to it — except that the standard does not set a wattage at all.

The bill is three numbers, and only two are published

The question looks like it wants a table of sizes with prices next to them. What it actually needs is the arithmetic, because the arithmetic is where the missing number lives. Annual cost is the hours the compressor runs, multiplied by the power it draws while running, multiplied by what a kilowatt-hour costs where you live.

Of those three, the price is genuinely published and genuinely traceable — the Energy Information Administration puts out a national average every month. The hours are published too, in a stranger way: the federal energy calculation contains an annual figure of 1,095 hours, which is the only number anyone has ever published for “how long does one of these run in a year”. The power draw is the one with no home. It is not on the carton, not on the EnergyGuide label, and not in the efficiency standard.

That last absence is the whole reason the answers you find online disagree with each other by a factor of two or three. They are not disagreeing about electricity prices. They are each quietly assuming a different wattage, and then presenting the result as though the wattage were a fact.

What the federal standard actually fixes

Portable dehumidifiers sold in the United States have to meet a minimum efficiency standard, and since 13 June 2019 that standard has been written as an integrated energy factor in litres per kilowatt-hour. It comes in three bands, and the bands are set by capacity in pints per day.

Read that table as a shopper and it looks like a ladder: bigger machines have to be more efficient. Read it as arithmetic and something else appears. A ratio of litres to kilowatt-hours does not cap the watts. It caps the watts per pint of water removed, which means the absolute wattage a legal unit may draw rises with its rated capacity inside every band, and then drops when the band changes.

An older standard, still in the regulation above this one, was written as a plain energy factor in the same units but with five bands and lower values — 1.35, 1.50, 1.60, 1.70 and 2.5. The two tables coexisting in one section is a useful reminder of how recent the current numbers are: a unit built before June 2019 was held to a weaker ratio, and the label on it still reads perfectly normally.

Working it out for three sizes

The derivation needs three published constants and one step of algebra. The federal procedure converts pints to litres using 1.04 pounds per pint and 0.454 kilograms per pound, which is 0.47216 litres per pint. It converts a daily capacity to an annual quantity by multiplying by 1,095 hours divided by 24. Dividing that annual water volume by the band’s minimum ratio gives the annual energy, and dividing the annual energy by 1,095 hours gives the average draw.

Written as one line, for a unit rated at C pints per day in a band whose minimum ratio is I:

The same four steps, run at the top of each band, give the three ceilings. Each one is the most a unit of that size may legally cost to run for 1,095 hours at the national average price:

Which row is yours

The table only helps if you know which line to read, and the line is decided by the size of the unit rather than by the size of the room.

• A 25-pint unit, typically a bedroom or a small closed room. Read the top row. It is the cheapest ceiling in the table, and the least useful comparison for anyone drying a basement, because a machine this size will not hold a damp basement whatever it costs to run.
• A 50-pint unit, the size most portable units are sold at. Read the middle row. It is the most expensive ceiling here, and it is also the row most households would be buying.
• A 70-pint unit, typically a basement or a whole floor. Read the bottom row. More capacity, a stricter ratio, and a ceiling below the middle one.

That is the whole reason “how much does it cost to run a dehumidifier” has no single answer even after the arithmetic is settled. The answer is a row, and the row is a size — not a brand, not a price, and not the number of pints on its own.

The middle size has the highest ceiling

A 70-pint unit removes 40 per cent more water than a 50-pint one, and it is allowed to cost less to run. That is not a mistake in the arithmetic; it is a step in the standard. Between 50.00 and 50.01 pints the required ratio rises from 1.60 to 2.80 litres per kilowatt-hour, a 75 per cent jump triggered by one hundredth of a pint.

Above that step, a machine can be bigger and still use less energy, because the ratio it has to hit more than covers the extra water. Below it, a 50-pint unit only has to reach 1.60, so it is permitted to draw 615 watts — more than the 70-pint machine above the step. The band boundaries, not the pint rating, are what the cost follows.

This has a practical consequence that runs against the usual advice. If you are choosing between a unit in the middle band and one just above it, and running cost is what you care about, the larger one is not the risky choice on electricity. It may still be the wrong choice for other reasons — a bigger unit cycling on and off in a small room removes less water per hour than its rating suggests, and a machine that short-cycles looks exactly like one that has failed — but the running-cost argument does not point where most people expect.

1,095 hours is an assumption, not a schedule

The number that does most of the work in every published estimate is the one nobody argues about. It arrives inside the federal energy calculation, where annual energy consumption is built from a two-hour test scaled up to 1,095 hours of dehumidification mode a year. Three hours a day is a modelling choice made so that units can be compared on a like-for-like basis. It is not a claim about how long your machine runs.

That distinction matters because the hours are the only term in the multiplication that a household actually controls, and the control is coarse. A unit left on continuously runs 8,760 hours a year, eight times the assumption. On the same watts and the same price, the 50-pint ceiling becomes $986 a year instead of $123.

Nothing here says a dehumidifier should run three hours a day. A damp basement in July is not the modelled case, and a unit that stops when the air reaches its setting will run far more in a wet week than in a dry one. The useful reading is narrower: any figure presented as “the annual cost” is a figure for a specific schedule, and the schedule is usually the federal assumption rather than yours.

The price has two dates, and neither is today

The price side is the part people trust most and check least. The number used here is 18.31 cents a kilowatt-hour: the United States total for the residential sector in July 2026, published on 24 September 2026. Three things about it are worth stating plainly, because each one is a way an estimate goes wrong.

It is a national total, not a state. Residential averages run well above and well below it, and the spread between states is larger than the spread between dehumidifier models. It is a ratio — revenue divided by kilowatt-hours sold — so it already contains transmission, distribution and the fixed charges that get folded into volumetric rates; it is not a tariff anyone can sign up to. And it carries two dates: the month the data describes and the day it was published, which are seven weeks apart by design. The figure was re-checked on 23 October 2026, the day the next monthly release was due, and the table still carried July 2026 and still read 18.31 — so the number in this page is current as of that check, not as of the day it was first read.

The rows scale linearly, which is the one genuinely reassuring thing about this arithmetic: doubling the price doubles the cost and changes nothing about the ranking. If your rate is above the national average, every number in this page moves up by the same proportion, and the middle band stays the expensive one.

The one multiplier a household controls

The humidity setting does not change the watts. It changes the hours. A unit set to hold a room at a given level runs until the sensor reads that level and then stops, so a higher setting means fewer running hours in the same weather — and the same machine, at the same wattage, costs less.

Published guidance from a manufacturer’s support page puts the usual bands at a bedroom setting of 55 per cent, a basement setting of 45 per cent, and a continuous mode that removes moisture above 15 per cent. The same page adds a detail that explains a lot of confusion about running costs: when the relative humidity is below or close to the minimum setting, water will not collect in the bucket or the drain hose at all. A unit that appears to be running for hours and producing nothing is often simply holding a room that is already at its target.

Two consequences follow for the annual figure. Setting a room to 45 per cent instead of 55 per cent buys a drier room with more running hours, and the cost difference is entirely a difference in hours, not in efficiency. And a unit in continuous mode is the one case where the 1,095-hour assumption is not just wrong but wrong by the largest possible factor, because continuous mode is designed to keep running.

None of that produces a number. What it produces is a way to read the numbers that do exist: an annual cost quoted for a dehumidifier is a cost for a setting and a climate, and both of those are yours to change.

What this page does not know

Three gaps are worth naming rather than filling.

The first is real-world wattage. The figures above are ceilings derived from a minimum standard, and a unit that beats the standard by a wide margin will cost materially less. This page has no measurement of any specific unit and does not pretend the ceiling is a typical value.

The second is duty cycle. Nothing published says what fraction of a year a dehumidifier in a given climate actually runs. The 1,095 hours is an assumption inside a calculation, and the honest statement is that the true figure depends on a house, a season and a setting.

The third is the price you pay. The national average is a real, traceable number and it is not your rate. Any estimate that stops at the national average is answering a question about the country rather than about your bill.

Questions this page answers

How much does it cost to run a dehumidifier?

Between $76 and $123 a year if the unit is built exactly to the federal minimum and runs the 1,095 hours a year the federal energy calculation assumes, priced at the July 2026 national average of 18.31 cents a kilowatt-hour. Those are ceilings rather than typical figures, because the efficiency standard is a floor that most units beat, and the 1,095 hours is an assumption inside a calculation rather than a schedule.

Does a bigger dehumidifier cost more to run?

No, and at the legal minimum it is the middle size that costs most. The federal standard requires 1.30 litres per kilowatt-hour up to 25 pints a day, 1.60 from 25.01 to 50.00, and 2.80 at 50.01 or more, so the requirement jumps 75 per cent at a single hundredth of a pint. Inverting those ratios gives a ceiling of about $76 for 25 pints, $123 for 50 pints and $99 for 70 pints at the national average price.

How many hours a day does that assume?

Three. The 1,095 hours a year that sits inside the federal energy calculation is 3.0 hours a day, and it is a modelling figure chosen so that units can be compared on the same basis, not a recommendation. A unit left on continuously runs 8,760 hours a year, which multiplies the annual cost by eight at the same wattage and the same price.

What humidity should I set my dehumidifier to?

Set it as high as the room tolerates, because the setting changes how many hours the machine runs and not the watts it draws while running. A manufacturer's published guidance puts the usual bands at 55 per cent for a bedroom, 45 per cent for a basement and a continuous mode that removes moisture above 15 per cent, and notes that water will not collect at all when the room is already below or close to the minimum setting.

Why is my bill higher than these figures?

Because 18.31 cents is a national average of revenue divided by sales, not a rate any household is charged. Residential averages vary widely between states, the figure already folds transmission, distribution and fixed charges into a volumetric price, and it describes July 2026 rather than today. The arithmetic scales linearly, so a rate above the national average raises every figure on this page by the same proportion.

Where these numbers come from

The three capacity bands and their minimum integrated energy factors — 1.30 litres per kilowatt-hour at 25.00 pints per day or less, 1.60 from 25.01 to 50.00, and 2.80 at 50.01 or more, for portable dehumidifiers manufactured on or after 13 June 2019 — together with the earlier five-band energy factor table of 1.35, 1.50, 1.60, 1.70 and 2.5 for units made on or after 1 October 2012, are from the federal energy conservation standards for dehumidifiers. The conversion constants of 1.04 pounds per pint and 0.454 kilograms per pound, the annual figure of 1,095 hours in dehumidification mode, the two-hour rating test period and the definition of integrated energy factor as litres of water removed per kilowatt-hour are from the federal test procedure for dehumidifiers. The residential average price of 18.31 cents per kilowatt-hour for July 2026, published 24 September 2026 and drawn from the United States total row rather than any state, is from the Energy Information Administration’s monthly electric power report; it was re-read on 23 October 2026, when the following monthly release was due and had not yet replaced the July figures. The bedroom setting of 55 per cent, the basement setting of 45 per cent, the continuous mode that removes moisture above 15 per cent and the note that water does not collect when humidity is below or close to the minimum setting are from a manufacturer’s published support page for a unit that has stopped removing moisture. The derivation of an average wattage from a ratio and a rated capacity, the three ceilings and their dollar values, the observation that the middle band carries the highest ceiling because the requirement steps at 50.01 pints, the reading of the two dates on the price, the eight-fold multiplier for continuous operation, and the three named gaps are our own working and are labelled as such where they appear. Nothing on this page is a test result. Where a figure is not published — the wattage of any specific unit, and the hours a machine actually runs in a year — we say so rather than filling the gap.