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Cost

How much a humidifier costs to run

The arithmetic is one line and the answer surprises people in both directions: a cool-mist unit is nearly free, and a warm-mist one is not.

By Scooter M. · Published · Updated

We earn a commission if you buy through the links on this page, at no extra cost to you. It does not change what we recommend or the order the picks appear in. Full disclosure. We show a live price when we have one and the words “Check price” when we do not. We never print a number we cannot currently verify.

How much a humidifier costs to run - ranked, with the arithmetic
#ProductBest forGal/dayPrice
1
No
image
Levoit Classic 160Top pick2.5 liters, 17 watts, and a base with no hard-to-reach corners. The smallest honest recommendation here, and the only one whose maker declines to claim a coverage figure at all.
A desk, a nursery corner, a small bedroom0.63implied · 188 sq ft
Check price#ad
2
No
image
Levoit Classic 300SA 6-liter tank, a genuinely wide top-fill opening and no filter to buy. Its own numbers describe a 190 sq ft machine, not the 505 sq ft on the box.
A bedroom you refill twice a week0.63implied · 187 sq ft
Check price#ad
3
No
image
Levoit Superior 6000SSix gallons, evaporative, and a Dry Mode that dries the wicks between runs. The 3,000 sq ft claim needs five times the output its own run time implies.
Mist-free humidification with a drying cycle2.0implied · 592 sq ft
Check price#ad
4
No
image
Levoit LV600S HybridWarm and cool mist from a 6-liter tank, and the only Levoit in this set that publishes a maximum output. On warm mist it genuinely covers a floor of a house.
The one unit here that publishes an output figure3.5published · 1,033 sq ft
Check price#ad
A domestic electricity meter on a wall
Licensed stock photograph, for illustration. It is not a photograph of any product on this page and we have not handled any of them.

Almost every answer to this question is the word inexpensive. That is not an answer, it is a mood. Here is the arithmetic, with the rate cited, so you can substitute your own tariff and your own hours.

We earn a commission if you buy through the links on this page, at no extra cost to you. It does not change what we recommend or the order the picks appear in. Full disclosure. We show a live price when we have one and the words “Check price” when we do not. We never print a number we cannot currently verify.

How much a humidifier costs to run - ranked, with the arithmetic
#ProductBest forGal/dayPrice
1
No
image
Levoit Classic 160Top pick2.5 liters, 17 watts, and a base with no hard-to-reach corners. The smallest honest recommendation here, and the only one whose maker declines to claim a coverage figure at all.
A desk, a nursery corner, a small bedroom0.63implied · 188 sq ft
Check price#ad
2
No
image
Levoit Classic 300SA 6-liter tank, a genuinely wide top-fill opening and no filter to buy. Its own numbers describe a 190 sq ft machine, not the 505 sq ft on the box.
A bedroom you refill twice a week0.63implied · 187 sq ft
Check price#ad
3
No
image
Levoit Superior 6000SSix gallons, evaporative, and a Dry Mode that dries the wicks between runs. The 3,000 sq ft claim needs five times the output its own run time implies.
Mist-free humidification with a drying cycle2.0implied · 592 sq ft
Check price#ad
4
No
image
Levoit LV600S HybridWarm and cool mist from a 6-liter tank, and the only Levoit in this set that publishes a maximum output. On warm mist it genuinely covers a floor of a house.
The one unit here that publishes an output figure3.5published · 1,033 sq ft
Check price#ad

Every unit in our set, for a full heating season

Season electricity cost at $0.1834/kWh, 182 days
UnitRated power8 h/night24 h/day
Levoit Classic 16017 W$4.54$13.62
Levoit Classic 300S26 W$6.94$20.83
Levoit OasisMist 1000S27.5 W$7.34$22.03
Levoit Superior 6000S30 W$8.01$24.03
Levoit OasisMist 450S280 W (warm mist)$74.77$224.31
Levoit LV600S280 W (warm mist)$74.77$224.31
Honeywell HCM350not published--
Vornado Evap40not published--
AIRCARE MA1201not published--
Aprilaire 70024 VAC transformernegligiblenegligible

Why warm mist costs so much more

Because it is doing physical work that the others are not. An ultrasonic unit vibrates a disc; an evaporative unit spins a fan. Both are moving water that is already liquid into the air using very little energy. A warm-mist unit boils it, and the energy needed to turn water into steam is large and unavoidable.

That is why the two 280 W units in our set are both hybrids with a heater. On cool mist alone they draw a fraction of their rated figure - Levoit rates them at the maximum, with the heater engaged. If you buy a hybrid and never use warm mist, you are in the cheap column. If you run warm mist all winter, the heater costs more per season than many of these machines cost to buy.

The three units with no published wattage

Honeywell, Vornado and AIRCARE publish no rated power on the pages we read. All three are evaporative units - a fan and a wick - so their draw is almost certainly in the same tens-of-watts band as the Levoit evaporative unit, and their season cost is very likely under ten dollars.

We are not going to put that estimate in the table. It is a reasonable inference and it is not a published figure, and the entire value of a table like this is that every number in it can be traced. A dash is more useful than a plausible guess, because a dash tells you something true about the manufacturer.

Your rate is not the national average

The 18.34 cent figure is a US average. Regional rates diverge enormously, and the ratio between them carries straight through the arithmetic.

What else costs money

  • Filters, on an evaporative unit. Usually the largest running cost, and four of six makers do not publish an interval. Filter replacement.
  • Distilled water, if you have hard water and an ultrasonic unit. At two gallons a day for a 182-day season that is 364 gallons. Which water.
  • Descaling supplies, which are pennies. White vinegar and a brush.
  • Heating, indirectly and in your favor: humid air feels warmer at the same temperature, which is one of the few genuine energy arguments for humidifying at all.

Add all of it up over a realistic ownership period and the ranking of these machines changes. That is done on the five-year total.

The picks, in full

No
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Top pick · A desk, a nursery corner, a small bedroom

Levoit Classic 160

2.5 liters, 17 watts, and a base with no hard-to-reach corners. The smallest honest recommendation here, and the only one whose maker declines to claim a coverage figure at all.

This is the only unit in the set where you can compute both ends of the range from published figures, because Levoit gives run times for minimum and maximum. 0.66 gallons over 25 hours is 0.63 a day; the same tank over 11 hours is 1.44 a day. At our derived rate that is roughly 188 to 427 square feet, and the honest way to state its coverage is exactly that: a range, with the setting attached.

Notice what Levoit did not do here: it did not put a square-footage number on the box. Given that every other model in its own line carries one that its published figures cannot support, declining to claim one on the smallest unit reads as restraint rather than an omission.

17 watts is the lowest draw in this set by a factor of one and a half, and the flat base with a wide opening is the single design decision that most reliably predicts whether a humidifier gets cleaned.

What works

  • Run time published at both minimum and maximum, so the output range can be computed
  • 17 W is the lowest rated draw here
  • Levoit publishes its own descaling procedure, including the soak time

What does not

  • 2.5 L means daily refills at anything above the lowest setting
  • No published coverage figure, so you have to do the arithmetic yourself
  • Ultrasonic, so the white-dust caveat applies

Skip this ifthe room is larger than a small bedroom. At maximum mist this empties in eleven hours and still only reaches the low four hundreds of square feet.

The arithmetic

Implied output (minimum mist)
0.63 gal/day
Covers, at 296 sq ft per gal/day
188 sq ft

Output derived as tank capacity divided by published run time, times 24. Coverage rate derived from Aprilaire’s own published capacity-and-coverage pairs.

Published specification

Tank
2.5 LAbout 0.66 US gallonsSource
Output/day
not published
Coverage
not publishedLevoit publishes no square-footage claim for this model, which is more honest than most
Run time
Up to 25 h low, up to 11 h maxBoth ends published, which lets you compute the rangeSource
Power
17 WSource
Noise
Under 28 dB at maximum mistSource
Filter
Pre-installed water filter spongeSource
Cleaning
Wide opening, no hard-to-reach corners in the baseLevoit's stated descaling method is a cup of white vinegar and water for 20 to 30 minutesSource
No
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Pick 2 · A bedroom you refill twice a week

Levoit Classic 300S

A 6-liter tank, a genuinely wide top-fill opening and no filter to buy. Its own numbers describe a 190 sq ft machine, not the 505 sq ft on the box.

The interesting number is not 6 liters, it is 60 hours. A 1.58-gallon tank that lasts 60 hours on low is moving 0.63 gallons of water a day, and 0.63 gallons a day is what covers about 187 square feet at the rate we derive from Aprilaire's own published sizing. That is a bedroom. It is not the 505 square feet on the specification table.

Both figures are true and they describe different settings. Levoit publishes the endurance of the quietest setting and the ceiling of the loudest, and never the output that connects them, so a buyer has no way to check the coverage claim. That is not a Levoit problem, it is a category problem, and it is the reason every roundup here shows the implied figure beside the claimed one.

What you are actually buying is the absence of a filter. No wick means no 30-to-60-day replacement cycle and no annual filter bill, and it also means every mineral in your tap water leaves the machine as white dust or stays behind as scale. Run low-mineral water or accept the descaling, which the EPA's own humidifier guidance is blunt about.

What works

  • No wick or replacement filter, so the running cost after purchase is water and 26 watts
  • 26 W is genuinely low: at the June 2026 US average tariff a full heating season of overnight running is a few dollars
  • The top-fill opening is wide enough to get a hand and a brush inside, which is most of what makes a humidifier easy to keep clean

What does not

  • The 505 sq ft coverage claim cannot be reconciled with the published tank and run time
  • Ultrasonic, so hard water becomes airborne white dust unless you use low-mineral water
  • Levoit publishes no gallons-per-day figure at any setting

Skip this ifyour water is hard and you will not commit to distilled. An ultrasonic unit atomizes whatever is dissolved in the tank, and this one has no wick to catch it.

The arithmetic

Implied output (low mist)
0.63 gal/day
Covers, at 296 sq ft per gal/day
187 sq ft
Maker’s coverage claim
505 sq ft
Output that claim would need
1.7 gal/day

Output derived as tank capacity divided by published run time, times 24. Coverage rate derived from Aprilaire’s own published capacity-and-coverage pairs.

Published specification

Tank
1.58 gal / 6 LSource
Output/day
not publishedLevoit publishes tank size and low-setting run time, not gallons per day
Coverage
215-505 sq ft / 20-47 m2Levoit's own figure. Its published tank and run time imply roughly 187 sq ft at our derived rate.Source
Run time
Up to 60 hOn the low mist settingSource
Power
26 WAC 120 V, 60 HzSource
Noise
30 dB or lessSource
Filter
None requiredA water filter sponge is included and descaling pads are sold separately, but there is no wick to replaceSource
Cleaning
Top-fill opening, brush includedLevoit's own wording: refill without flipping the tank overSource
No
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Pick 3 · Mist-free humidification with a drying cycle

Levoit Superior 6000S

Six gallons, evaporative, and a Dry Mode that dries the wicks between runs. The 3,000 sq ft claim needs five times the output its own run time implies.

Six gallons over 72 hours is two gallons a day, which covers about 590 square feet. The box says 3,000. To actually hold humidity across 3,000 square feet this unit would need to move a little over ten gallons a day, and at that rate its six-gallon reservoir would run dry in about fourteen hours. Both numbers describe the machine; only one describes it at a time, and the maker publishes no figure that reconciles them.

Dry Mode is the genuinely good idea here and it deserves credit. A wet wick sitting in a warm room is the substrate for everything the EPA warns about, and a fan cycle that dries the wicks between runs attacks that problem directly rather than adding an antimicrobial coating and hoping. It also extends wick life, which is the recurring cost.

Thirty watts to move two gallons a day is efficient, and mist-free operation means the minerals stay in the wicks rather than settling on your furniture. If you can live with a coverage claim you should mentally divide by five, this is a well-made machine.

What works

  • Dry Mode addresses the real failure mode of evaporative units instead of masking it
  • Mist-free, so no white dust whatever your water is like
  • 30 W for six gallons of capacity, with noise published at both ends of the range

What does not

  • The 3,000 sq ft claim is about five times what the published tank and run time imply
  • Four wicks to replace, on an interval Levoit does not publish
  • 45 dB at the top of the fan range is audible in a quiet bedroom

Skip this ifyou bought it for the 3,000 sq ft number. Size it at around 600 square feet on the setting whose run time Levoit actually publishes.

The arithmetic

Implied output (low fan speed)
2.0 gal/day
Covers, at 296 sq ft per gal/day
592 sq ft
Maker’s coverage claim
3,000 sq ft
Output that claim would need
10.1 gal/day

Output derived as tank capacity divided by published run time, times 24. Coverage rate derived from Aprilaire’s own published capacity-and-coverage pairs.

Published specification

Tank
6 gal / 22.7 LSource
Output/day
not published
Coverage
3,000 sq ft / 279 m23,000 sq ft needs about 10.1 gal/day at our derived rate. Its published tank and run time imply 2.0.Source
Run time
Up to 72 hOn the low fan speedSource
Power
30 WSource
Noise
28-45 dBSource
Filter
Four wick filters, pre-installedReplacements are sold by Levoit as a four-pack. No replacement interval is published.Source
Cleaning
Dry ModeLevoit's own wording: low and high fan speeds dry out the elevated wick filters, extending filter lifeSource
No
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Pick 4 · The one unit here that publishes an output figure

Levoit LV600S Hybrid

Warm and cool mist from a 6-liter tank, and the only Levoit in this set that publishes a maximum output. On warm mist it genuinely covers a floor of a house.

This is the only unit in the portable group whose maker publishes an output rate, and publishing it is worth crediting. 550 mL an hour is 13.2 liters a day, which is 3.49 gallons a day, which covers roughly 1,030 square feet at our derived rate. That is more than its own 753 sq ft claim, so for once the box is conservative.

The catch is the setting. 3.49 gallons a day on maximum warm mist empties a 6-liter tank in about eleven hours and draws 280 watts while it does it. On the lowest setting the same machine moves 0.76 gallons a day and covers about 224 square feet. One box, a four-and-a-half-fold range, and only the two ends published.

280 watts is the number to think about if you plan to run warm mist all winter. Boiling water is not free, and this is the page where that becomes a real line on a bill rather than a footnote.

What works

  • Publishes an actual output rate, which almost nobody in this category does
  • Warm mist is genuinely useful in a cold room and slightly reduces microbial growth in the tank
  • 6 liters with a 753 sq ft claim that its own maximum output can actually support

What does not

  • 280 W rated: warm mist all season is a real electricity cost, not a rounding error
  • Maximum output empties the tank in about eleven hours
  • The gap between lowest and highest setting is roughly 4.5x, and only the two extremes are published

Skip this ifyou want to run it flat out overnight and forget it. At the published maximum it needs refilling before morning.

The arithmetic

Published output (lowest mist)
3.5 gal/day
Covers, at 296 sq ft per gal/day
1,033 sq ft
Maker’s coverage claim
753 sq ft
Output that claim would need
2.5 gal/day

Output as the manufacturer publishes it. Coverage rate derived from Aprilaire’s own published capacity-and-coverage pairs.

Published specification

Tank
1.58 gal / 6 LSource
Output/day
550 mL/h max warm mistLevoit publishes this as an hourly rate. Over 24 hours that is 13.2 L, or 3.49 gallons per day.Source
Coverage
430-753 sq ft / 40-70 m2Source
Run time
Up to 50 hOn the lowest mist settingSource
Power
280 WThe heater dominates. Cool mist alone draws far less.Source
Filter
Water filter sponge, 2 suppliedA sponge, not a wick. No scheduled replacement interval is published.Source
Cleaning
Descaling pads sold separatelySource

Questions people actually ask

How much does it cost to run a humidifier?

For a cool-mist unit, very little: a 26 W humidifier run eight hours a night for a 182-day heating season uses 37.9 kWh, which is $6.94 at the US average residential rate of 18.34 cents per kWh. A 280 W warm-mist unit over the same nights costs about $74.77.

Are humidifiers expensive to run?

Only if they boil water. Ultrasonic and evaporative units draw 17 to 30 watts and cost single-digit dollars for a season of overnight use. Warm-mist and hybrid units draw up to 280 watts with the heater on and cost roughly ten times as much.

How many watts does a humidifier use?

In our set: 17 W for the smallest Levoit ultrasonic, 26 to 30 W for the larger cool-mist and evaporative units, and 280 W rated for the two hybrids with a warm-mist heater. Three manufacturers - Honeywell, Vornado and AIRCARE - publish no wattage at all for the units we looked at.

Does running a humidifier increase your heating bill?

Marginally in electricity, and it can work in your favor on heating. Humid air feels warmer at the same temperature, so some people find they can hold a slightly lower thermostat setting. We are not going to put a figure on that saving, because it depends on your house and your habits and we have no way to measure it.

Is it cheaper to run a humidifier all night or all day?

The cost is directly proportional to hours, so 24-hour running costs three times what eight hours costs. For most people overnight running in the bedroom is where the benefit is concentrated anyway, and it is also gentler on the filter.

Sources

Every figure on this page came from one of the documents below, read on the date shown. We do not cite other review sites, forum posts or video reviews as sources of fact.

Read next

Found a number that is wrong? Tell us and we will fix it and say so. How we pick shows every formula used on this page.