Heating dries out indoor air, and dry air feels colder on your skin. A small humidifier fixes that for a few cents a night, if you pick the right type.
Quick answer: for most bedrooms, get a small cool-mist humidifier that fills from the top, and aim for 30 to 50% humidity. Cool mist costs about 4¢ a night to run. Warm mist boils the water, so it costs roughly ten times more and the steam is hot.
| Pick | Best for | Link |
|---|---|---|
| Levoit Top Fill Humidifier, 2.5 L | Best for most bedrooms | Check price on Amazon |
| DREO 4 L Humidifier (HM311) | Best for refilling less often | Check price on Amazon |
| Levoit Evaporative Humidifier, 4.5 L | Best if you have hard water | Check price on Amazon |
| Vicks Warm Mist Humidifier, 1 gal | Best if you want warm mist | Check price on Amazon |
Best for most bedrooms
A small cool-mist humidifier that fills from the top, so refilling it is a quick pour instead of carrying the tank to the sink. Listed at 25 dB, quiet enough to sleep next to.
Watch out: Ultrasonic models can leave white dust with hard tap water; use distilled water if you see it.
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Best for refilling less often
A bigger 4 L tank listed at up to 36 hours of run time, so one fill covers a few nights in a bedroom.
Watch out: Rinse and dry the tank every few days so nothing grows in standing water.
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Best if you have hard water
An evaporative humidifier pushes air through a wet wick instead of making mist, so it leaves no white dust on furniture, and output naturally slows as the room gets more humid.
Watch out: The wick is a running cost; it needs replacing every few months.
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Best if you want warm mist
Boils water into a warm mist, which some people prefer in a cold bedroom. Filter-free, so there is nothing to replace.
Watch out: Boiling uses far more power than cool mist (see the calculator), and the steam is hot: keep it away from kids and pets.
Check price on AmazonHow it's worked out: watts ÷ 1000 × hours × your rate, with the humidifier running the whole time. Typical figures: ultrasonic cool mist 20 to 40 W, evaporative 10 to 40 W, warm mist 200 to 400 W. Check the label on yours.
A little. In very dry air, moisture evaporates off your skin faster and that cools you, so the same 68°F can feel chilly. Bringing the humidity back up to the 30 to 50% range makes the room feel more comfortable at the same thermostat setting. It won't replace a heater, but it can make a degree or two lower easier to live with. For real warmth at night, a heated mattress pad costs about 10¢ a night.
Aim for 30 to 50%. Below about 30% the air feels dry and static builds up. Above 50%, windows start to fog, and damp can lead to mold, especially on cold outside walls. A cheap hygrometer tells you where you are; some humidifiers have one built in.
Both add the same moisture to the room. Warm mist boils the water, so it uses much more electricity and the steam can scald. Cool mist (ultrasonic or evaporative) is cheaper to run and safer around kids and pets. Ultrasonic models can leave white dust if you use hard tap water; evaporative models don't.
Empty, rinse and dry the tank every few days and follow the maker's cleaning steps. Standing water is what makes a humidifier smell or grow mold.
Slightly. Dry air makes moisture evaporate off your skin faster, which feels cold. Raising humidity to 30 to 50% makes the same temperature feel more comfortable, but it doesn't heat the room.
Between 30 and 50%. Lower feels dry; higher can fog windows and encourage mold on cold walls.
A cool-mist ultrasonic humidifier uses about 30 W, roughly 4¢ for an 8-hour night at 17.5¢ per kWh. A warm-mist model uses about 300 W, roughly 42¢ a night.
For most people, cool mist: it costs less to run and has no hot steam. Choose warm mist only if you prefer the feel and can keep it out of reach of children and pets.