Levoit LV600S Smart Warm & Cool Mist Humidifier Review

Heated winter air is dry air — it's common for a furnace-heated house to sit at 20% relative humidity in January — and dry air makes a room feel colder than the thermostat says, dries out sinuses and skin, and shrinks wood floors. Getting a bedroom back to 40% is the cheapest way to feel warmer at the same thermostat setting. The LV600S does it automatically: tell it 45%, and its sensor cycles the mist to hold there, which is the feature that separates humidifiers you actually use from ones that end up in a closet.

The warm-mist option is worth having. Boiling the water before it's atomized sterilizes it (a real benefit for an ultrasonic, which otherwise aerosolizes whatever's in the tank), and the warm vapor takes the edge off a cold bedroom. Cool mist is there for the rest of the year. The 6-liter tank lasts a day or two between fills in a bedroom on auto mode, it's near-silent on low, and the VeSync app handles schedules and voice control well. The aroma tray is a pleasant extra.

Two rules make it a good owner experience. First, distilled or demineralized water: ultrasonic humidifiers turn dissolved minerals into a fine white dust that settles on everything, and distilled water eliminates it. Second, clean it weekly — a vinegar soak and a scrub of the base and warm-mist chamber — because every humidifier grows film in a week and a dirty one is worse than none. Do both and it's the best all-round humidifier we've tested for winter comfort.