10 Best Furnace Humidifier Options

A furnace-mounted, or whole-house, humidifier connects to a forced-air heating system to deliver moist air throughout the house. There are a few different types of furnace humidifiers. A flow-through humidifier uses freshwater that flows through the system and drains away. A reservoir type has a reservoir of water that moistens a rotating drum. A steam humidifier heats water to create steam that is injected into the furnace airflow.

Of the three, flow-through humidifiers are often preferred because they are more reliable and usually more hygienic than reservoir types, and they are less expensive and use less electricity than steam units.

A flow-through humidifier typically is mounted to the furnace’s cold-air return duct and connects to the hot-air supply off the furnace through a humidifier supply takeoff duct. The takeoff duct diverts some heated air into the humidifier, where it absorbs moisture from an evaporator pad before returning to the warm air stream through the cold-air return duct and furnace.

Some flow-through humidifiers are mounted directly to the hot air supply duct and do not use a supply takeoff duct.

Furnace Humidifier Components

Although there are some variations to the components of a humidifier, they all require:

• Water (to create humidity)
• Water collection medium (e.g., evaporator pad)
• Blowing air (causes evaporation)
• Water control valve (solenoid) or float
• Humidistat (controls humidity setting)

Many of the components of a flow-through humidifier are shown here. This is how all the parts work together:

• Water tap/supply line: A water supply line for the humidifier is tapped into an existing water pipe. 
• Water inlet orifice: The orifice reduces the water flow to the humidifier inlet valve.
• Water inlet valve: This valve allows water to flow to the humidifier based on demand. The valve is usually electrically operated by a solenoid controlled by the humidistat. 
• Water feed tube: Distributes water to the distribution trough under the top cover, and feeds water to the evaporator pad.
• Evaporator pad (media): This is the water collection medium that holds the water briefly as it is evaporated to create humidified air.
• Drain pan: Water flows through the evaporator pad and into the drain pan, from which it flows out into a household drain.
• Air damper/air duct: Some models have an air duct from the hot-air side that supplies air to the humidifier mounted on the cold-air return. If the home has central air conditioning, a damper is required.

Best Overall:

Honeywell HCM-350 Germ-Free Cool Mist Humidifier at Amazon

“Quiet, efficient, and easy to use according to experts and owners.”

Best for Large Spaces:

Essick MA1201 at Amazon

“This model is powerful enough to moisten the air in the entire house.”

Best for Bedrooms:

Pure Enrichment Ultrasonic Cool Mist Humidifier at Amazon

“It’s quiet, compact, easy to use, and effective.”

Best Budget:

TaoTronics Ultrasonic Cool Mist Humidifier at Amazon

“It has the added effect of keeping your skin healthy and hydrated.”

Best Splurge:

LEVOIT Humidifier, 5.5L Warm and Cool Mist at Bed Bath & Beyond

“Releases cold or warm mists, so you can use it for many uses.”

Best Portable Humidifier:

VAVA Ultrasonic Humidifier at Amazon

“It can cover most large rooms around 500 square feet.”

Best Warm Mist:

Vicks Warm Mist Humidifier at Amazon

“An easy travel option to take with you wherever you go.”

Best for Baby:

Crane USA Humidifiers at Amazon

“Easy to clean and functions at a very low decibel.”

Best With Diffuser:

URPOWER Essential Oil Diffuser Cool Mist Humidifier at Amazon

“Relieve any dry symptoms while also adding a spa-like scent.”

Best Design:

TaoTronics Cool Mist Humidifier at Amazon

“Matches sleek design with remarkable functionality.”

Buying Guide

If your home or office is feeling dry and stuffy, you’re in need of a humidifier. These small appliances add moisture to air that has become dry from central heating or dry environmental conditions.

Humidistat:

For an optimal level of humidity in the air, look for a model with a built-in humidistat. This feature will monitor the room’s humidity and shut off the appliance when the air’s moisture level hits a set target.

Size:

The size of the humidifier you choose will largely be based on the size of the room you’re looking to add moisture to. There are basically three sizes of humidifiers on the market: Portable (also called Tabletop), Console, and Whole House.

Water Tank Capacity:

Closely related to the size of the humidifier you choose is the water tank capacity. Look at the estimated run time from the manufacturer to see how often you’ll need to refill the tank. If you want to use the humidifier all day or all night—or both—make sure you pick a model with a large enough capacity.

Auto-Shutoff:

Many humidifiers on the market are equipped with an auto-shutoff feature. This is important if you plan to leave your humidifier on for extended periods of time, since it will switch off the unit if it runs out of water.

UV Filtration:

Since moist, humid conditions can quickly become a breeding ground for bacteria, mold, and pathogens, some humidifiers are equipped with a UV light. The specialized light filtration system eliminates microbes that may be growing in the humidifier’s tank and prevents them from being released into the air with the mist.

Demineralization Cartridge:

If you have hard water, strongly consider a humidifier with a demineralization cartridge.

Air Filter:

For allergy sufferers, a humidifier with a pre-filter to clean incoming air may be a smart idea.

Product Types

Warm Mist:

As its name implies, a warm mist humidifier releases moisture into the air in the form of warm mist.

Cool Mist:

There are two primary types of cool mist humidifiers on the market: evaporative and impeller. Each one varies in the way it operates, but they both release a room-temperature mist that humidifies your space.

Evaporative:

This type of cool mist humidifier relies on a filter (sometimes referred to as a wick) that picks up water from a reservoir below. A fan blows air across the filter, where it picks up moisture through evaporation, and then the mist is propelled out of the humidifier.

Impeller:

An impeller humidifier is equipped with a rapidly spinning disc that sends water to a diffuser, where it’s transformed into tiny droplets capable of being transferred as mist into the surrounding room.

Ultrasonic:

Of all humidifiers, an ultrasonic is the quietest option. While many models are cool mist humidifiers, there are some that let you opt for either a cool mist or warm mist mode. Cool mist ultrasonic humidifiers are one of the most popular types of humidifiers on the market. 

Brands

Honeywell:

Honeywell is known for their home heating and cooling devices, so it’s no surprise that they make a well-rounded selection of humidifiers. In fact, Honeywell even offers whole-house humidifiers in addition to more than a dozen portable humidifier models. Most of the models are cool mist humidifiers, with some warm mist options available as well.

Vicks:

Famous for their congestion-relief products, Vicks makes a number of different humidifiers designed to work in tandem with their medicated vapor pads

Levoit:

Levoit focuses on improving the comfort of your home’s air supply with a small but capable selection of humidifiers. There are both cool mist and combination models to choose from, but the real attraction here is the larger water tanks and longer running times of Levoit humidifiers—up to 40 hours of runtime for some models, and over 750 square feet of coverage for others.

HoMedics:

A leading manufacturer of small home appliances, HoMedics offers primarily ultrasonic humidifiers.

Crane:

With distinctive water droplet-shaped humidifiers, Crane makes devices that are eye-catching yet functional.

Cleaning

Keeping your humidifier clean is a crucial aspect of humidifier maintenance. All humidifiers will need to have the water tank regularly cleaned to ensure that harmful bacteria and microbes don’t take up permanent residence.

To avoid this spread of bacteria, it’s advisable to drain and dry your humidifier’s reservoir before refilling. At least once a week, you should clean and descale your humidifier with vinegar and sanitize with bleach or a specially formulated humidifier cleaning agent.

Warranties

Since most humidifiers are considered small home appliances, warranty coverage is generally limited. Many models include one-year limited warranties that cover defects in manufacturing or workmanship. Some more advanced models, including some ultrasonic humidifiers, increase the warranty period to three years.