A humidifier's power bill is the cheapest thing about owning one.
The expensive part pours out of a jug.
Run a cool-mist unit ten hours a night through a winter and the electricity comes to roughly $6.
Fill that same unit with store-bought distilled water and you spend about $156 over the same nights.
Everything below is a variation on that ratio.
Quick facts
- Cool-mist electricity: about $6 per winter
- Warm-mist electricity: about $61 per winter
- Distilled water: about $156 per winter
- Wick or filter refills: about $35 per winter
Where the money goes over one winter
Every number here assumes ten hours a night for 120 nights, at the U.S. average residential rate of roughly 17 cents per kilowatt-hour.
Your own rate is printed on your bill, and it can be well under that in the Northwest or well over it in New England.
Look up the current average electricity rateU.S. Energy Information Administration โ
One winter of a warm-mist unit run on distilled water, 10 hours a night for 120 nights.
Cool mist costs $6 a winter, warm mist costs $61
An ultrasonic humidifier vibrates a small metal plate at a frequency far above hearing.
That costs about 30 watts, less than an old-style bedside bulb.
Across a winter it draws roughly 36 kilowatt-hours, which is the $6.
Evaporative models add a fan and a wick and land in the same neighborhood.
A warm-mist unit boils its water, and boiling is the most expensive thing a small appliance can do.
Expect 200 to 400 watts whenever the element is on.
Call it 300 watts and a winter runs about $61.
That is still not a big number. It is simply ten times the other one.
What you buy with it is sterilized steam and a slightly warmer room.
Nobody shops for a humidifier by its water bill, which is exactly why the water bill wins.
The water is the real line item
Ultrasonic mist carries whatever minerals were in the tank, and those minerals land on your furniture as white dust.
Distilled water ends that, at $1.10 to $1.50 a gallon at a grocery store.
A 1.5-gallon tank emptied most nights is roughly 120 gallons a season.
That is the $156 โ more than several of these machines cost new.
Larger tanks drink faster on high; the capacity numbers for one of them sit in the Levoit LV600S Review.
Tap water is free and perfectly fine in an evaporative or warm-mist unit, where minerals stay behind in the tank instead of riding out on the mist.
In an ultrasonic unit, tap water is a trade rather than a saving: no water cost, more dusting, more descaling.
Filters, wicks, and half an hour of vinegar
Evaporative wicks stiffen with mineral scale and stop absorbing long before they look used up.
Plan on one every four to six weeks at $10 to $14, so about $35 a winter.
Ultrasonic units use cheaper absorbent cartridges, and some use none at all.
Descaling costs white vinegar and half an hour a week, which rounds to nothing.
Skipping it is what turns a $70 humidifier into a one-season humidifier.
The cost that never lands on a receipt
Running a room past 50 percent relative humidity is the one genuinely expensive mistake here.
Water condenses on the coldest surfaces first โ window frames, exterior walls, the back of a closet.
Mold follows standing moisture, and remediation is not a $6 line item.
A Brief Guide to Mold, Moisture and Your HomeU.S. Environmental Protection Agency โ
Hold the room between 30 and 50 percent and the machine gets cheaper to own in every column at once.
