Expert consulted: 
Dry winter air can leave you with chapped lips, itchy skin, and a scratchy throat, especially when your home's heating system is running nonstop. A humidifier can help, but choosing between a cool-mist and a warm-mist humidifier isn't as straightforward as you might think.
Experts at the Good Housekeeping Institute Home Improvement & Outdoor Lab have tested dozens of humidifiers over the years, including 25 models in their latest review. Their testing covers everything from moisture output and noise levels to energy use and ease of cleaning.
For most households, a cool-mist humidifier is the better choice, particularly if you have young children or pets. But warm-mist humidifiers have advantages, too. Here's how the two compare and what to consider before buying.
Cool-mist humidifiers
Pros:
- Safer for kids and pets: No hot water or steam to cause burns.
- Energy-efficient: Uses less electricity because it doesn't need to heat water.
- Quiet operation: Ultrasonic models are typically very quiet, making them ideal for bedrooms.
- Versatile: Works well year-round, especially in bedrooms and nurseries.
Cons:
- White dust: Ultrasonic models can disperse minerals from tap water, leaving a fine residue on furniture.
- Fan noise: Evaporative models can be louder than ultrasonic options.
- Filter replacements: Evaporative models require periodic wick or filter replacements.
- Regular cleaning: Tanks and internal components need frequent cleaning to prevent bacterial and mold growth.
Warm-mist humidifiers
Pros:
- Quiet operation: Most models don't use a fan, though some make gurgling sounds.
- Less white dust: Boiling water generally keeps minerals inside the machine rather than dispersing them into the air.
- Warm vapor: The heated mist can feel more comfortable during cold winter months.
Cons:
- Burn risk: Hot water and steam can cause burns, making these models less suitable for homes with young children or pets.
- Higher energy use: Heating water requires more electricity than most cool-mist technologies.
- Mineral buildup: Heating elements can accumulate scale and need regular descaling.
- Regular cleaning: Even with boiling water, these humidifiers still need frequent cleaning to prevent buildup and contamination.
Is cool mist safer around kids and pets?
The American Academy of Pediatrics recommends cool-mist humidifiers for children because they don't pose the hot-water and steam-burn hazards associated with warm-mist models. A warm-mist humidifier can cause burns if a child touches the heated components, gets too close to the steam, or knocks over a unit containing hot water.
Cool-mist humidifiers eliminate those particular hazards, making them a better choice for nurseries, children's bedrooms, and homes with curious pets. That doesn't mean they're completely risk-free. Position every humidifier carefully and clean it regularly.
How much cleaning does a humidifier need?
Neither type of humidifier is maintenance-free, but some are easier to clean than others. Regardless of the type, the Environmental Protection Agency recommends emptying, drying, and refilling portable humidifiers daily, with a thorough cleaning every three days.
For daily upkeep, unplug the humidifier, empty any leftover water, wipe down accessible surfaces, and refill with fresh water. Every three days, clean the tank and other water-contact surfaces to remove mineral buildup and residue, following the manufacturer's instructions. Replace filters, wicks, and demineralization cartridges as recommended.
At the end of the season, give the humidifier one final cleaning and let all components dry completely before storing it in a dry place.
What should you look for before you buy?
Before buying a humidifier, consider your room size, noise level, and maintenance needs. Check the manufacturer's recommended coverage area, and remember that a larger tank means fewer refills, not necessarily better performance. Ultrasonic cool-mist models are typically the quietest and most energy-efficient, while warm-mist models use more electricity to heat water.
Safety and air quality matter, too. Cool-mist humidifiers are the safer choice for homes with young children because they don't produce hot steam. If you have allergies or asthma, avoid excess humidity, which can encourage mold and dust mites. Whichever type you choose, regular cleaning is essential to prevent bacteria and mold buildup.
Which humidifier makes the most sense for your home?
For most homes, our experts recommend a cool-mist humidifier. Ultrasonic models are a good choice for bedrooms because they're quiet and compact, though using distilled water helps prevent white dust from collecting on furniture. Evaporative models are less likely to produce mineral dust or excess moisture on nearby surfaces, but their fans can be noisier.
Warm-mist humidifiers are worth considering for adult-only spaces if you prefer warm vapor and don't mind higher energy use. Just remember that hot water and steam pose a burn risk, especially around children and pets.
For more shopping advice, check out our humidifier buying guide, which covers features like tank size, humidity controls, and ease of cleaning. You can also browse the Good Housekeeping Institute's tested humidifier recommendations to find the right model for your home.
A few more humidifier questions
Is it safe to sleep with a humidifier running all night?
Yes, as long as the humidifier is properly maintained, safely positioned, and doesn't raise the room's humidity above recommended levels.
For overnight use, choose a model with a humidistat and automatic shutoff. Make sure the mist isn't directed at your pillow, bedding, or nearby furniture.
Can you use tap water in a humidifier?
Tap water contains minerals that ultrasonic humidifiers can disperse into the air, creating white dust. Distilled water is the better option for reducing this residue.
Evaporative and warm-mist models generally disperse fewer minerals, but hard water can still cause scale inside the machine. Always follow the manufacturer's water recommendations.
Can you add essential oils to a humidifier?
Many humidifiers are designed for water alone, and adding oils directly to the tank can damage internal components.
Some models have separate aromatherapy trays or compartments. Use those only as directed, and be especially cautious about fragrance exposure around children, pets, and people with respiratory sensitivities.
Will a warm-mist humidifier heat a room?
A warm-mist unit releases some heat along with moisture, but it won't replace a space heater. Its main job is humidification, not temperature control.
Why trust Good Housekeeping?
Former editorial director at the Good Housekeeping Institute and longtime product tester, reviewer, writer, and editor Jessica Teich wrote this story. Most recently, Senior Reviews Analyst Olivia Lipski and contributor Timothy Dahl updated it; they cover everything from consumer electronics to home, outdoor, fitness, and more. They consulted the Good Housekeeping Instituteโs Home Improvement & Outdoor Lab Director Dan DiClerico and the Labโs extensive testing data.
Having written thousands of product reviews and how-to articles on all aspects of home ownership, from routine maintenance to major renovations, Dan (he/him) brings more than 20 years of industry experience to his role as the director of the Home Improvement & Outdoor Lab at the Good Housekeeping Institute. A one-time roofer and a serial remodeler, Dan can often be found keeping house at his restored Brooklyn brownstone, where he lives with his wife and kids.
