How much does it cost to run a humidifier?
About $2.21 a month on the typical usage below, at the U.S. average $0.1816/kWh. Set your own rate and usage and the figure updates instantly.
Cool-mist humidifiers sip ~30W; warm-mist (boiling) types can pull 200–300W.
Running a humidifier at 40W for 10 h a day costs about
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A humidifier's cost depends almost entirely on which kind you own, and the spread is huge. A cool-mist ultrasonic unit uses a tiny vibrating disk to shake water into fog — it sips around 30 watts, barely more than a phone charger, because it never has to heat anything. A warm-mist humidifier, on the other hand, is really just a small water boiler: it has to bring water to a rolling boil to make steam, which takes 200-300 watts, seven to ten times more power for the same jug of water.
That's why the honest answer to "what does my humidifier cost" is really two answers. Run a cool-mist unit all night through a dry winter and it barely registers on the bill. Run a warm-mist model the same way and it starts costing real money — not because it humidifies better, but because boiling water is inherently expensive. If your only goal is cheap, steady humidity, the wattage on the box matters more than the brand.
What drives the cost of running a humidifier
- Cool-mist vs. warm-mist design — ultrasonic/cool-mist units use ~20-30W (just a vibrating plate), while warm-mist (steam) units use 200-300W because they're actively boiling water
- Tank size and humidity setting — larger tanks and higher target humidity make the unit (or its heating element, for warm-mist types) run more of each hour instead of cycling off
- Hours per day — most people run a humidifier overnight or all day during dry winter months, so total runtime, not just wattage, drives the monthly total
How to cut it
- Choose a cool-mist (ultrasonic or evaporative) model over a warm-mist one if operating cost matters — it's the single biggest lever, often a 7-10x difference
- Set it to a target humidity (40-50%) with a built-in hygrometer/humidistat instead of running it on max nonstop — it'll cycle off once the room is humid enough
- Close the door to the room you're humidifying so the unit isn't fighting to raise humidity in a larger volume of air than it needs to
- Size the humidifier to the room — an oversized unit for a small bedroom just cycles on and off inefficiently, or runs on a low, wasteful trickle setting
Data basis
- Electricity price
- U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.B, June 2026 year to date, released 2026-08-26. Retrieved 2026-09-11. Average residential revenue per kWh. A benchmark average, not a utility tariff — it excludes the fixed charges, tiers, time-of-use windows, taxes and fuel adjustments on a real bill.
- Appliance energy
- A representative running power for a humidifier, compiled from published manufacturer specifications and public appliance-energy guidance, and presented as a typical figure with the usual range shown above. It is not a measurement of your unit, and we do not claim a single primary source for it — the nameplate on your appliance, or an hour with a plug-in energy meter, beats any typical figure we can publish.
- Usage model
- Steady load — 40W for 10 h a day
- International prices
- rounded typical household tariffs for each market, in that market's own currency unless the row says US$ equivalent. These are planning benchmarks with no single primary source; enter the per-kWh price from your own bill for an accurate figure.
- Last reviewed
- 20 August 2026. Next scheduled review 20 February 2027.
- Corrections
- Think a figure is wrong? Tell us at corrections@watt-dollar.com and see our corrections policy.
Common questions
How much does it cost to run a humidifier per month?
On the assumption shown above — 40W for 10 h a day — a humidifier costs about $2.21 a month, or $26.51 a year, at $0.1816/kWh. That price is the U.S. average; set your own rate and usage above and the figure updates.
How is that worked out?
Power drawn while running x hours run per day. At 40W for 10 h a day that is 0.40 kWh a day, which at $0.1816/kWh costs $0.07 a day.
How can I cut the cost of running a humidifier?
Choose a cool-mist (ultrasonic or evaporative) model over a warm-mist one if operating cost matters — it's the single biggest lever, often a 7-10x difference As a worked example: running it 8 h a day instead of 10 h takes it from $26.51 to $21.21 a year, about $5.30 less.
Do I really pay that every year?
Only if you run it every day. Most people don't: over a typical 150-day dry months the same usage comes to about $10.90. The annual figure assumes daily use all year.
Is a humidifier cheaper to run than a dehumidifier?
Usually yes, if it's a cool-mist humidifier — a cool-mist unit's ~20-30W is far below a dehumidifier's typical 300-700W compressor draw. A warm-mist humidifier, though, can cost about as much as a small dehumidifier since both pull 200W+ continuously.
Does a warm-mist humidifier humidify a room faster, or is the extra cost wasted?
It doesn't add moisture to the air any faster in most rooms — both types raise humidity at a similar rate for the same tank size. The warm-mist unit's higher wattage goes into boiling the water, not into moving more moisture into the air, so the extra cost buys warmth at the vent, not speed.