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5 Best Furnace Humidifiers of 2024

Updated
Five products to humidify your whole house.

Do you find yourself coughing and sniffling a lot in the colder months? This may be because of the low humidity in the air.

Furnace humidifiers can be life savers in the winter — especially if you live in a particularly dry climate. The dry air can irritate your skin and make breathing uncomfortable. This could lead to respiratory problems (1).

The best furnace humidifier adds moisture to the air that’s already being heated in your home. You just simply attach it to your home’s central heating, ventilation, and air conditioning (HVAC) system.

It can be hard to know which furnace humidifier to choose. We spent hours researching expert advice, real customer reviews, and dozens of products. In conclusion, we narrowed it down to five furnace humidifiers that are highly effective, easy to use, and have handy features.

Our Top Picks

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Image
Model
Product Comparison Table
Features

Product Image of the GeneralAire 1000A Humidifier
Best Overall
GeneralAire 1000A Humidifier
  • Excellent 18 gallon output
  • Easy installation
  • Small and lightweight
Product Image of the Aircare MA1201 Humidifier
Best Cool Air Furnace Humidifier
Aircare MA1201 Humidifier
  • Built-in humidistat
  • Easy clean-up
  • Four fan settings
Product Image of the Aprilaire 600 Automatic Humidifier
Best Budget Furnace Humidifier
Aprilaire 600 Automatic Humidifier
  • Great budget pick
  • Programmable settings
  • Water panel change indicator
Product Image of the Honeywell HE300A1005
Best for Large Homes
Honeywell HE300A1005
  • Automatic control
  • Easy installation
  • Powerful performance
Product Image of the Emerson HSP2000 Steam Humidifier
Most Advanced Furnace Humidifier
Emerson HSP2000 Steam Humidifier
  • Thermal fan interlock
  • Auto-flush
  • Steam-powered


The Best Furnace Humidifiers of 2024

After days of extensive research, we’ve shortlisted the best furnace humidifiers. This list is a culmination of industry expert advice, our own experiences, and user feedback.

What did we look for? Primarily what type of humidifier it was, its effectiveness, coverage area, maximum output, and how much customers loved it. Let’s get into the top five.

GeneralAire 1000A Furnace Humidifier

Best Overall

The 1000A from GeneralAire is our favorite because of its light weight and powerful performance. It’s fan-powered, meaning it’s more efficient in evaporating water, thus creating more moisture.

Weighing only four pounds, you’d never think this little machine could produce a whopping 18 gallons per day. But it can cover about 3,000 square feet, which is ideal for medium-sized houses.

Our favorite thing about this furnace humidifier is its extra features. It has an automatic mode fitted with an outdoor sensor for temperature control. This means you don’t have to worry about turning it on or off, and it’ll automatically determine the moisture needed in the house.

What We Like

Excellent Maximum Output

Given its small size and weight, the 1000A can produce 18 gallons per day. This adequately covers most medium-sized houses.

Easy to Install

Users comment on how user-friendly the instructions are. They provide a good amount of detail about wiring the humidifier.

Take Note

Although it’s marketed as 120V, it only requires 24V. You also don’t need a contractor to install it.

Small Size and Weight

It weighs only four pounds and measures 14.75 by 16 by 10 inches. This makes it ideal for even the most cramped furnace room. It also makes it easy to carry around if you need to move it.

Includes Automatic Digital Humidistat

This comes with a fitted automatic humidistat which senses the outdoor temperature. This means it will automatically determine the moisture needed, so you don’t have to worry about guesswork. It also ensures the humidity levels don’t exceed certain levels, which can cause condensation.

On the other hand, if you prefer manual operation, there is an option for that, too.

UV Stable Plastic Construction

This humidifier is made from durable UV stable plastic. If you have a UV lamp nearby, then this will hold up.

What We Don't Like

Loud Noise

Just like other fan-powered furnace humidifiers, it does make noise. The fan makes a considerable amount of noise when it’s at full speed with the heat turned up. If your furnace is located in a furnace room or closed space, this shouldn’t be an issue.

Warranty Only Valid if Fitted by Contractor

This product includes a 10-year warranty, which is great for the price. But the warranty is only valid if you hired a contractor to install it. Considering it’s so easy to install yourself, that’s quite inconvenient.

But if you get your 10-year warranty, we do recommend hiring a contractor for installation.

Product Specs

Type Fan-powered
Coverage Area 3,000 square feet
Dimensions 14.75 x 16 x 10 inches
Maximum Output 18 gallons per day
Weight 4 pounds

Our Ratings

Installation Compatibility
4.5 / 5
Maintenance Requirements
3.5 / 5
Water Efficiency
4.5 / 5
Coverage Area
5 / 5
Total Rating
4.25 / 5

User Experience

Excellent installation experience with this product, although cutting a large hole in sheet metal can be a bit challenging. The humidistat is user-friendly with large, clear backlit numbers and an outdoor temperature monitor, which is especially useful in areas with fluctuating temperatures. While the fan noise is noticeable, it's not overly loud and wouldn't be an issue if the unit is in a basement.

Aircare MA1201 Whole-House Furnace Humidifier

Best Cool Air Furnace Humidifier

This furnace humidifier adds cool moisture into the air as opposed to steam. It can humidify up to 3,600 square feet and has a maximum output of 12 gallons per day.

The best thing about this humidifier is its electronic controls and built-in humidistat. You can control the humidity through the control settings. It gives you a range between 25 and 65 percent.

The humidifier adjusts automatically to the fan speed needed to achieve the desired humidity. What’s great about including a digital humidistat is that it maintains the humidity with digital accuracy.

Did we mention it’s really easy to clean and requires minimal maintenance? If it needs to be refilled or the filter needs to be changed, it will notify you on the indicator.

What We Like

Built-In Humidistat

The featured digital humidistat automatically keeps the humidity at your desired level without manual input. It’ll automatically turn off when it’s reached the desired level, which you can set through the easy-to-use control settings.

Easy Clean-Up

This humidifier doesn’t have many moving parts — you won’t find any belts, pulleys, or wheels. This makes for easy cleanup, with the bonus of an evaporative wick that effectively traps mineral deposits.

Four Fan Settings

You can choose from four different fan speeds to control how much humidity you want to be pumped out into the air. This gives you more control over your energy consumption.

It also has an auto-mode which will sense the air for you and choose a suitable humidity level. When it reaches it, it will automatically shut off.

3,600 Square Feet Coverage

Putting out 12 gallons per day, this can humidify a whole house up to 3,600 square feet. For a standalone unit, this is mighty impressive.

What We Don't Like

Filter Replacements

The filters need to be changed often and can be pricey. Overall, this amounts to significant upkeep costs, which can be annoying.

Mist Cools Down a Room

Customers noticed that the cool mist wasn’t super appreciated in winter. It actually can cool down a room, making you even colder.

Noticeable Noise Level

Even the most satisfied customers found that this was a pretty noisy humidifier. If you like quiet, cozy nights, this might get on your nerves.

Product Specs

Type Fan-powered
Coverage Area 3,600 square feet
Dimensions 20.5 x 21.5 x 14.5 inches
Maximum Output 12 gallons per day
Weight 14 pounds

Our Ratings

Installation Compatibility
4 / 5
Maintenance Requirements
3 / 5
Water Efficiency
4 / 5
Coverage Area
4.5 / 5
Total Rating
3.75 / 5

Personal Perspective

Best whole home humidifier I've tried! This product effectively covers over 3,000 sqft, keeping my main living area and master suite comfortably humid. The evaporative fan disperses moisture evenly and operates quietly on lower settings (F1 and F2). The Auto setting is helpful, but I recommend using independent hygrometers to gauge room humidity, as the cord hygrometer reads higher due to its proximity to the unit. Maintenance is simple, with the removable side container making for easy filling and cleaning. Although the fan can be loud on higher settings, the benefits of this humidifier, such as relief for my dry, cracked hands, make it a worthwhile purchase.

Aprilaire 600 Automatic Humidifier

Best Budget Furnace Humidifier

This is the only bypass furnace heater on our list, but it’s still a high performer. Given its affordability, it still has a wide area coverage of 4,000 square feet.

It also has a maximum output of 16.8 gallons per day, so you’re not compromising much here, even though it’s the budget pick. It’ll cover a large home and can diffuse moisture efficiently.

Our favorite thing about this humidifier is that it allows you to set it and forget it. You can program your desired humidity settings by the week or by day.

This programming feature is perfect if you want to conserve energy while away from home. You can control the humidity level as you like — higher when you’re home and lower when you’re away.

What We Like

Great Budget Pick

It’s the most affordable humidifier on our list. Yet it has a great coverage area and impressive maximum output.

Program Device to Suit Your Schedule

You can program this humidifier to work around your schedule. If you want to lower it while you’re away from home, it’s totally doable. You also can set it and forget it — it can run on a seven-day program that you specify.

Water Panel Change Indicator

It’s recommended that the water panel be replaced twice a year. You don’t have to worry about remembering, though. Each model has a helpful indicator that alerts you when it’s time for a replacement.

Built-In Bypass Damper

This is an in-duct bypass humidifier that is compatible with your HVAC system. It uses a more natural evaporation process to create more evenly distributed humidity. In fact, it creates around 50 percent more moisture than other furnace humidifiers.

What We Don't Like

Requires Furnace to Always Be On

Given that it’s not fan-powered, it can’t run on its own. It requires the motor from the furnace to add humidity to the air. Users comment on how this means a higher energy consumption.

Not Great in Poorly Sealed Homes

If your home has average or loose sealing, it won’t be as effective in larger areas. For instance, if you’re in a loosely sealed home, this will only be effective in areas up to 1,500 square feet.

Requires Professional Installation

Since this is to be installed in your HVAC unit, it’s best to get a professional to install it.

Product Specs

Type Bypass
Coverage Area 4,000 square feet
Dimensions 15 x 10 x 16 inches
Maximum Output 16.8 gallons per day
Weight 11 pounds

Our Ratings

Maintenance Requirements
4 / 5
Water Efficiency
4 / 5
Coverage Area
5 / 5
Total Rating
4.25 / 5

Community Feedback

Great product overall, but be prepared for a lengthy installation process. I found that using sheet metal snips provided the most precise cuts during installation, and connecting the copper supply line for water was easier than expected. Once installed, the humidity in my house increased significantly, and the exterior temperature sensor kept the humidity well-adjusted. Although the unit is more efficient with hot water, I found it still works effectively with cold water, which may save some energy costs.

Honeywell HE300A1005

Best for Large Homes

The HE300A1005 is another powerful fan-powered humidifier. It has the same maximum output as the GeneralAire 1000A at 18 gallons per day. The catch is that this humidifier can cover up to 4,000 square feet. This makes it ideal for large homes with multiple rooms.

It features HumidiPRO Digital Humidity Control technology, meaning it automatically controls the moisture level in your home. This doesn’t require manual intervention, so you can just set it and forget it. It also modulates the water intake to maintain consistent humidity as your furnace switches on and off.

Users comment on how easy it is to install. It can be hooked up to a hot or cold water line, but it works best with hot. Keep in mind, however, that this may increase energy consumption significantly.

What We Like

Automatic Control

The HumidiPRO digital control lets you leave it running all day without adjusting it manually. You’ll have the perfect moisture level all day.

Easy to Install

This humidifier comes with an easy-to-follow professional installation guide. It’s a one-piece design with mounting screws around the perimeter. That means installing it in one step rather than mounting a separate frame assembly.

It’s also suitable for any type of home, including condos or townhouses.

Powerful Performance

This humidifier can output up to 18 gallons per day and cover 4,000 square feet. This means if you have a larger home, this product will suffice. It will even work for a medium-sized home with many rooms.

Saves You Money and Water

One thing we love about this is that it will reduce your heating bills. It saves thousands of gallons of water annually due to only running when needed. In turn, this will save you a ton of money on your heating bills.

Noise Reduction Technology

Furnace humidifiers can be loud. But this one has operational noise reduction to ease sound levels slightly.

What We Don't Like

Large Size and Heavy Weight

It weighs about 16 pounds and is relatively large, with dimensions of 15.5 x 16.8 x 10.3 inches. This means it won’t fit into all furnace ducts and takes up a lot of space in small furnace rooms. Be sure you have adequate space for it.

A Reputation for Leaking

We recommend hiring a professional to install this. If you don’t, you could be facing some leaking issues.

Product Specs

Type Fan-powered
Coverage Area 4,000 square feet
Dimensions 15.5 x 16.8 x 10.3 inches
Maximum Output 18 gallons per day
Weight 16.2 pounds

Our Ratings

Installation Compatibility
4 / 5
Maintenance Requirements
3.5 / 5
Water Efficiency
5 / 5
Coverage Area
5 / 5
Total Rating
4.25 / 5

First-Hand Impression

I recently installed the Honeywell HE300A1005 TrueEASE Humidifier and it has made a noticeable difference in my home's air quality. The passive operation is great, and I found that using hot water instead of cold improves the humidification performance. Although it took some time to find the best spot for installation, it was worth the effort. Be aware that the unit can use a lot of water, but the energy efficiency and improved air quality make it worth it for me. Just remember to clean the humidifier pad regularly to keep it running efficiently.

Emerson HSP2000 Steam Furnace Humidifier

Most Advanced Furnace Humidifier

We love the HSP2000 from Emerson because of its cutting-edge technology. It features a thermal fan interlock that allows the humidifier to add moisture without heat. This means it’s energy- and money-saving since it can sense when the humidity is low but when the temperature is fine.

Another great feature is the safety cutoff switch. Its built-in overflow protection means you’ll never have to worry about a short circuit due to overcharge. It also features a flushing timer you can manually set to flush out any excess water that wasn’t evaporated.

The Emerson also comes with a chlorine removal filter so that the moisture distributed to your home is free of toxins and harmful elements.

In terms of coverage, it’s ideal for small to medium size houses — not larger than 1,850 square feet.

What We Like

Thermal Fan Interlock

This humidifier doesn’t need your furnace to be on to add moisture into the air. It can save you a lot on energy bills.

The humidity level isn’t necessarily tied to temperature levels — sometimes, the house is warm but filled with dry air. This unit from Emerson can provide optimal humidity control while considering the home temperature.

Auto-Flush and Chlorine Removal Filter

These two features work hand in hand to ensure your filter is running mold and bacteria-free. The chlorine removal filter allows you to fill it with tap water, while the auto-flush works every two hours and ensures no mildew buildup.

Safety Cutoff Switch

The blower safety switch gives you peace of mind because you don’t have to worry about overcharging the unit due to the featured overflow protection. You can keep the humidifier running automatically without worrying about power issues. This is unique to this product only.

Steam Powered Humidifier

Perhaps the most unique thing about this product is it’s steam-powered. Not only does this ensure exact humidity control, but the unit is also made of stainless steel. This ensures more durability.

Another benefit is that it doesn’t require the furnace to be running first. When the unit detects low humidity levels, the steam is turned on. This triggers a thermal switch that turns on the furnace blower.

What We Don't Like

Difficult Installation

The unit comes with instructions as to how to install it. However, customers mention it can be challenging to install since it needs to be placed in the vertical output of the furnace. This often requires building a transition for the unit.

Unless you’re super savvy with these types of things, you’ll probably need a professional to do it for you.

Difficult to Clean

To clean this unit (which you need to do every few weeks), it’s a bit of a hassle. You have to remove and disconnect parts while avoiding the unit’s electrical parts.

Product Specs

Type Fan-powered
Coverage Area 1,850 square feet
Dimensions 7.6 x 12.5 x 12.6 inches
Maximum Output 13 gallons per day
Weight 18.1 pounds

Our Ratings

Installation Compatibility
4 / 5
Maintenance Requirements
4 / 5
Water Efficiency
4.5 / 5
Coverage Area
3 / 5
Total Rating
3.75 / 5

User Experience

I recently replaced my old Honeywell TrueSteam humidifier with the HSP2000 and have been extremely satisfied with the results. The HSP2000 is an all-metal, ultra-simple designed humidifier that is built to last, unlike the fragile, plastic Honeywell model. Installation was straightforward, and the unit has been working efficiently throughout the season. One downside is that the metal box containing the electronics tends to get quite hot during operation, and it may benefit from some passive ventilation. This humidifier is perfect for those who are looking for a durable, reliable solution to maintain a comfortable humidity level in their home. Just be prepared for a slightly more complex cleaning process, as some disconnection is required.

Product Comparison Chart

Product Best Type Coverage Area Dimensions Max Output Weight
GeneralAire 1000A Furnace Overall Pick Fan 3,000 sq ft 14.75 x 16 x 10″ 18 gal/day 4 lbs
Aircare MA1201 Whole-House Cool Air Furnace Humidifier Fan 3,600 sq ft 20.5 x 21.5 x 14.5″ 12 gal/day 14 lbs
Aprilaire 600 Automatic Budget Furnace Humidifier Bypass 4,000 sq ft 15 x 10 x 16″ 16.8 gal/day 11 lbs
Honeywell HE300A1005 For Large Homes Fan 4,000 sq ft 15.5 x 16.8 x 10.3″ 18 gal/day 16.2 lbs
Emerson HSP2000 Steam Advanced Furnace Humidifier Fan 1,850 sq ft 7.6 x 12.5 x 12.6″ 13 gal/day 18.1 lbs

Why You Need a Furnace Humidifier

Here are the top reasons you might benefit from one of these devices.

Cost-Effective

Furnace humidifiers are better than portable humidifiers because of their ability to diffuse moisture throughout your entire house. Plus, if you have multiple rooms in your home, it would be costly to buy several small humidifiers.

Counteract Furnace Drying Effect

Furnaces produce dry-heated air. In the winter, this can be particularly harsh on your sinuses and respiratory system, leading to colds and sore throats.

What’s more, dry air affects more than just your health. It can dehydrate wood products that need moisture to “breathe.”

Furnace humidifiers, though, add moisture or humidity into the air through water vapor. They make breathing more comfortable, but they also work to hydrate your plants and wood floors.

How to Choose a Furnace Humidifier

When searching for the best furnace humidifier, there are various factors and features to consider. Not all furnace humidifiers are created equally, and not all fit your family’s needs or home dimensions! Here’s what to keep an eye out for.

Type

There’s a wide range of furnace humidifiers out there, and they all work differently to increase moisture levels in the air. However, what they all have in common is that they all produce steam and push it through the HVAC ductwork.

There are two main types:

Fan-Powered Furnace Humidifiers

These types of humidifiers are also known as evaporative. They work simply by exposing the furnace-heated air to water. The hot air evaporates, slowly increasing the level of moisture in the ducts.

These common furnace humidifiers require minimal maintenance and are super easy to install. You’ll just have to change the filter or water panel every year.

Having a built-in fan means you’ll always have a steady air movement. This allows more water to evaporate consistently and efficiently, increasing the humidity.

Evaporative humidifiers have a dedicated fan and aren’t reliant on hot air convection. Therefore, you can use evaporative humidifiers while the furnace isn’t in use,

However, this ability to circulate air and increase humidity on their own makes them a bit more expensive than bypass humidifiers.

Bypass Furnace Humidifiers

Bypass humidifiers are less expensive than evaporative humidifiers. This is partly because they don’t come with a fan or steamer. This means they’re entirely dependent on your home furnace system.

They use the blower motor of the furnace. Moisture is added to the air and then recirculated to the furnace, where the blower motor pushes the air into the space. This redistribution causes some of the moisture to be lost in the process.

If you get distracted or annoyed by whirring fan noises, a bypass furnace humidifier might be a better choice for you. They make minimal noise since there’s no fan. There are also fewer moving parts than an evaporative humidifier, meaning less maintenance.

Keep In Mind

Bypass furnace humidifiers don’t increase humidity as much as fan-powered humidifiers. As a result, they aren’t great for large spaces.

Coverage

The coverage area will help you determine whether the furnace humidifier can reach all areas of your home sufficiently.

When choosing a model, marry up the coverage area to your home’s area in square feet. Subtract the square footage of rooms that aren’t connected to your HVAC duct system.

Don’t purchase a furnace humidifier with a larger coverage area if you have a small apartment. You’ll only be wasting water and electricity.

Size and Weight

The dimensions of your furnace humidifier will depend on the size of your furnace room, basement, or attic. If you have a super tiny furnace room, you don’t want to cramp an oversized furnace humidifier in there. So make sure to measure your space first.

The size and weight also impact the efficiency and coverage area. If you have a larger house, you’ll have more space to accommodate a larger humidifier.

Maximum Daily Output

This is directly related to the coverage area. A larger coverage area means higher maximum output in 24 hours.

This is measured in gallons per day. 16 gallons a day of water output is enough to cover 3,000 to 4,000 square foot areas. If you have a smaller home, look for humidifiers with even lower maximum daily output.

Also, keep in mind that more output means more energy consumption. So high-output humidifiers can increase your electricity and water bills if overused.


FAQs

How Much Does It Cost to Add a Humidifier to a Furnace?

The amount it costs to add a humidifier to a furnace depends on two things: whether you get the pros to do it or call in a handyman/woman. The pros charge between $75 and $150 an hour, while a handyman/woman charges between $50 and $80 an hour.

Do Humidifiers on Furnaces Cause Mold?

Humidifiers on furnaces can cause mold. When you increase the moisture content of the atmosphere, it encourages fungal growth, especially black mold.

Where Should a Humidifier be Installed on a Furnace?

The humidifier should be installed on a furnace near the water supply and electrical outlets, but away from air conditioning coils, and other HVAC components. The humidifier should also have access to the indoor air supply.

How Long Do Furnace Humidifiers Last?

The time a furnace humidifier lasts depends on how well you maintain it and the amount of usage it gets. Most will last a minimum of five to ten years.

How Do You Maintain a Furnace Humidifier?

The best way to maintain a furnace humidifier is to use filtered or distilled water in the reservoir, clean it regularly, and change or clean the filter.

How Often Should You Change Your Furnace Humidifier Filter?

You should change your furnace humidifier filter every three months, depending on the amount it gets used. If you live in a drier climate, you may need to do this more frequently.


A Humidifier for Your Entire Home

Each furnace humidifier in this list delivers a powerful performance. They’re sure to fill your home with much-needed moisture in the dry winter months.

Of prime importance, however, is not choosing a model that’s too large for your home. This is easy to avoid by checking the areas covered by your HVAC system. Measure these spaces and then consult our recommended best furnace humidifiers to narrow down your options.

The manufacturers gain their products’ unique selling points by adding extra bells and whistles. Good options to look for here are automatic sensors and the ability to pre-program the unit for an extended period.

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Headshot of Matthew Sullivan

About the Author

Matthew Sullivan

Matthew Sullivan is a technical writer with over 15 years of hands-on experience in the realm of HVAC, humidity, air purification, and mold prevention. With a background rooted in mechanical engineering, Matthew seamlessly blends the intricate world of technicalities with the everyday challenges that homeowners and businesses face. His vast expertise has led him to collaborate with leading HVAC manufacturers, consult on cutting-edge air purification systems, and become a sought-after voice on mold mitigation.