Buyers Guide & Information

6 Best Furnace Humidifiers

Our comparisons cover the top-rated brands that produce moist & healthy air.

An adequately humid environment helps us breathe better and also ensures that homes, people, pets, and plants stay healthy. So it is undoubtedly an excellent idea to invest in stand-alone humidifiers or add a furnace humidifier to your HVAC system.

Read on through our best home furnace humidifier reviews to find out the perfect unit for your needs!

The concept is simple — the furnace produces dried up heated air, and the humidifier kicks in to moisturize it before delivering it outward.

The process to do so differs depending on the type of selected furnace humidifier.

For instance, if you have a fan-powered or evaporative humidifier, the resulting air flows through the water as some of it gets evaporated and moisturizes the air.

On the other hand, bypass humidifiers do the same thing, but differently — on the way out, the air passes through the humidifier’s soaked pad and carries moisture along with it.

Quick Guide – Our Top Picks


Best Flow-Through Model

Honeywell Home HE360A1075 HE360A
Honeywell Home HE360A1075

Our Top Pick

Aprilaire 400
Aprilaire 400

Best Value For Money

Aprilaire 700M
Aprilaire 700

Furnace Humidifiers Vs. Console Models

Both these units humidify a place, but they operate in different ways. Console humidifiers are plug-and-play devices, whereas a furnace humidifier needs to be installed to the HVAC system.

To ensure the right amount of humidity, a control unit will have to be put somewhere in your home or office.

  • Since Furnace humidifiers are connected to the ducts, the humidity spread is more uniform across the home or office space, as opposed to console units.
  • A furnace humidifier produces about four times more humidity.
  • A water pad or furnace humidifier filter needs replacing annually or bi-annually and doesn’t require special upkeep, whereas it takes a lot of time and effort to maintain console humidifiers.
  • The best furnace humidifier units are a bit pricier than console units, but well worth it because of performance.
  • A Furnace humidifier delivers around the clock performance and is best for big homes, whereas console units are best for daily usage in small rooms and houses.

Furnace Humidifiers Compared

ModelTypeRoom SizeDaily Humidity OutputPrice
Aprilaire 400Bypass1,250 – 4,000 sq ft17 GallonsCheck Sylvane

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Honeywell Home HE360A1075Flow-Through2,700 – 4,500 sq ft18 GallonsCheck Sylvane

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Aprilaire 800 SteamSteam6,200 sq ft11.5 – 34.6 GallonsCheck Sylvane

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Skuttle 190-SH1Drum/ Bypass1,848 – 4,048 sq ft17 GallonsCheck Sylvane

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GeneralAire 1000AFan Power3,000 sq ft18 GallonsCheck Amazon
Aprilaire 700Fan Power2,100 – 4,200 sq ft18 GallonsCheck Sylvane

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Buying the Right Furnace Humidifier

Humidifier Types Explained

Drum Humidifiers

The humidifier has a rotating bypass tube that uses a rotating drum to source water. All air passing through the ducts goes through this tube and is moisturized via evaporation and then dispersed.

Flow-Through Humidifiers

Like a drum humidifier, a flow-through one also has a water evaporation mechanism and a tube. However, the water source is different. Instead of using a pre-filled container, a constant stream of water is sprayed to the humidifier pad, so it can continue to operate.

Fan-powered Humidifiers

If your HVAC setup is installed in a tight space, fan-powered units are your best bet due to their small size and sheer power.

They don’t require a tube, bypass ducts, or backing from a furnace. A fan is used to disperse moisture in the air when need be.

Steam Whole Home

A steam humidifier for furnace is way powerful than all other options, because many times, evaporation does not lead to acceptable humidity levels.

Instead of using an evaporation mechanism, electricity comes into play to produce moisture. Not only is the produced vapor more, but it is much easier to control humidity levels with a steam furnace humidifier.

Room Coverage

No matter how big or small your house is, you’ll find a suitable furnace humidifier that can keep the moisture acceptable.

Most units available have a coverage area of 1,500 square feet. Some of the best furnace humidifier units may have maximum coverage of 3,000 to 8,000 square feet.

Be careful, though. You need to strike a balance, and the humidifier has to be the right size – if it’s too big, it may over-moisturize and waste a considerable amount of water and power. In contrast, a unit that’s too small for your spaces won’t humidify the area properly.

Setup & Installation

Furnace humidifier installation may differ depending on the type of unit you buy. If you selected a flow-through or drum furnace humidifier, it would be installed to the bypass ducts, where the air intake is done through the supply plenum, and the mist is dispersed from the outer duct. It’s your call whether you want to install it to the return air duct or plenum.

If you have a steam humidifier for furnace, call in an expert to ensure your safety during the installation as a heating element is involved. This one can also be added to the return air duct or plenum, and the choice is entirely yours. However, you may need to arrange for a specialized power outlet as most steam-based furnace humidifier units operate on 240-volts.

Daily Humidity Output

It is important to maintain suitable levels of humidity because too much of it also has certain risks.

Some units can produce 12 gallons a day, others can do 19, and so on — select a furnace humidifier that provides the right amount of humidity, i.e., at par with the available space, plus, it should have a good-sized water tank.

It would be best to monitor the humidity levels daily, so you can benchmark what should be regarded as comfortable.

Weight & Dimensions

Unlike a console unit, a whole house furnace humidifier needs to be attached to the HVAC system. This is why it is best to know its dimensions to judge if it can fit the available space.

It is quite possible that your furnace room is small, or you have to carry the humidifier high up to the attic or down below to the basement to install it. So it makes sense to invest in one that is easy to carry, weighs less, and has a small footprint.

On the other hand, in bigger homes, you may have a decent space that’s big enough for good-sized units.

System Compatibility

Even if you get your hands on the best hot air furnace humidifier, it will be pointless if the unit is not compatible with your pre-installed HVAC system.

For instance, you may have a heat pump or an HVAC system that works with a thermostat; the whole house furnace humidifier should also work similarly and not on its own accord.

Extra Features

Here are some features worth considering when narrowing the focus to the right unit:

  • Water Reservoir Change Indicator
  • Low Water Cutoff
  • Automatic Operation
  • Overflow Protection
  • Mounting Frames
  • Corrosion Resistant
  • Reversible Side Panels


Furnace humidifier costs account for different brand names and the features they offer. Plus, you also have to consider the cost to install a humidifier for a furnace as professional help is required – the technician may charge you by the hour.

That said, here are ballpark figures:

  • Drum and bypass units cost around $150 to $250
  • Flow-through units cost between $200 to $250
  • Steam furnace humidifiers cost around $450 to $700+

With installation, steam units can cost you around $1,500+, whereas other furnace humidifier units can cost $500 to $1,000.


A generous warranty period safeguards your investment and signifies that you have selected a quality unit built to last.

Get one that offers at least a year’s worth of coverage. Make a note of the terms and conditions to know when you can make a claim, and when the warranty is inadmissible or void.

You will be happy to see that some of the best humidifiers for hot air furnace units are backed with a five or ten-year warranty.

6 Best Furnace Humidifiers Reviewed

1. Aprilaire 400

Our Top Pick
Room Coverage1,250 – 4,000 sq ft
Daily Humidity Output17 Gallons
Dimensions16 x 16 x 11 inches

If you have a decent-sized home or office, you can either place stand-alone humidifiers in different rooms or connect one to your HVAC system for an even spread. The latter is undoubtedly a better idea, and we recommend you to go with the Aprilaire 400.

According to the performance reviews, this is the best furnace humidifier for mid-size houses, and hence the top pick for our furnace humidifier reviews.

This bypass unit is best for homes sized 1,250 to 4,000 square feet; it does an impressive job, especially in sealed areas.

You get both options – to manually adjust the humidity levels – or to set a level and let the unit maintain it.

On the auto-mode, a bypass damper kicks in when humidity levels change and get it back to the assigned level.

This Aprilaire furnace humidifier also requires less water than other units on the market, and cleaning it is quite straightforward. It would be best to hire an expert to install it.


  • Five-year warranty
  • Good coverage area
  • No floor drain needed
  • Reversible side panels


  • Not good for older homes that are not fully sealed
  • DIY installation voids the warranty

2. Honeywell Home HE360A1075

Best Flow-Through Furnace Humidifier
Room Coverage2,700 – 4,500 sq ft
Daily Humidity Output18 Gallons
Dimensions10.25 x 15.25 x 14 inches
HumidistatYes (H8908)

If you live up north or anywhere where climatic conditions are dry, you better invest in a humidifier. A good option would be to go with a flow-through model that does an excellent job – and doesn’t cost a lot. Per our research, the best flow through furnace humidifier is the Honeywell Home HE360A1075.

This Honeywell furnace humidifier also checks all the right boxes, as it can moisturize a well-insulated area of up to 4,500 square feet.

But it has to be installed correctly, so it would be best to call in an expert technician. This is not one of those units you should fiddle with unless you have a good idea of what you need to do.

If you plan to DIY the installation, please check how to do it online and follow the directions that come with the unit.

This whole house furnace humidifier does not feature a water container, which isn’t much of loss as you no longer need to worry about hard water deposits or the formation of bacteria. However, you may notice a slight hike in your water bill as some wastage may be involved.

Plus, the Honeywell Home HE360A1075 has to have good drainage to ensure that there are no leaks.


  • Humidistat included
  • Installation is easy
  • Compact size
  • Good coverage


  • One year warranty
  • Installation kit to be bought separately

3. Aprilaire 800 Steam

Best Furnace Humidifier For Large Homes
Room Coverage6,200 sq ft
Daily Humidity Output11.5 – 34.6 Gallons
Dimensions8 x 11 x 21 inches
HumidistatYes with a dual sensor

If you have an ample space, humidifying it end-to-end is no job for a stand-alone humidifier. You need something way sturdier like the Aprilaire 800 Steam.

It features a heating-plate to produce moisture instead of the evaporation method, and we feel that it is the best furnace humidifier for large homes.

It is rated to thoroughly moisturize homes up to 6,200 square feet in the most efficient manner as it can produce a maximum of 34.6 gallons of humid air per day, which is beyond impressive.

For best results, this Aprilaire furnace humidifier should be connected to a 240-volts power outlet. But it can also work at 120-volts if the need by, although not as efficiently.

The reason it deserves a spot in our best home furnace humidifier reviews is that as a steam-based unit, it produces much more humidity than an evaporative unit.

It uses a fill valve to bring water to the featured leak-proof electrode canister. Then the provided heating element heats the water till it’s boiling – this is where it derives the moisture to make your air more humid.

Though a bit heavy, the Aprilaire 800 Steam is still quite easy to install to the cold-air return. Once operational, it will keep running as long as the temperature stays between 40 degrees Fahrenheit and 99 degrees Fahrenheit.

The provided Humidistat monitors the humidity within the house and also looks at the outside temperature. Then it adjusts accordingly to keep the moisture at acceptable levels.


  • Five-year warranty
  • Electrode canister change indicator
  • Coverage up to 6,200 square feet
  • Auto and continuous mode


  • Bulky

4. Skuttle 190-SH1

Best Furnace Drum Humidifier
Room Coverage1,848 – 4,048 sq ft
Daily Humidity Output17 Gallons
Dimensions11.69 x 10.75 x 10.94 inches
HumidistatYes (SK0-0055-001 Manual)

Breathing in dry air is never comfortable, as your health and home get adversely impacted. It would be best to add a whole house furnace humidifier, and the Skuttle 190-SH1 is a good choice.

It is one of the best furnace drum humidifier units that can be installed in your current HVAC system. A continuous rotating drum hosts an absorbent pad, and heat from the furnace evaporates some of the water soaked by the pad. It gets infused with the hot air, which then moves outwards from the vent.

Once this unit is connected to the Humidistat, set the desired humidity levels, and the humidifier kicks in every time the moisture falls or rises.

Skuttle 190-SH1 can deliver 17 gallons of moisture per day when the plenum temperature is at 120 degrees. When the house is fully insulated, it can provide an even spread for up to 4,048 square feet.

Add to that the fact that it has reversible components for seamless fitting, water usage is minimal, features a shutoff damper, and it comes with an installation kit.


  • Rust resistant
  • Easy to clean
  • Energy efficient
  • Installation kit included


  • One-year warranty

5. GeneralAire 1000A

Best Fan Powered Furnace Humidifier
TypeFan powered
Room Coverage3,000 sq ft
Daily Humidity Output18 Gallons
Dimensions21 x 19 x 18 inches
HumidistatYes (digital)

If you make calculated investments and want to ensure that your asset remains safe for years down the lane, we recommend you to go with the GeneralAire 1000A — it comes with a generous ten-year warranty.

It is rated as one of the best fan powered furnace humidifiers, and known for a uniform spread of moisture in areas as big as 3,000 square feet.

As a fan-based unit, it doesn’t depend on the furnace for much. Instead, it uses the built-in motor to pull in the warm air, which gets moisturized when passed through the evaporative vapor pad. Then this moisture-infused air is blown out from the ducts across the house.

The solenoid collar doesn’t come pre-tightened, so it would be best to involve an expert when installing; otherwise, you may face leakage.

Thanks to the Humidistat, you just have to pick the right settings on the GeneralAire 1000A, and it monitors and keeps the humidity on the assigned level. The featured sensor also monitors the outside temperature and adjusts the humidity accordingly.

However, you may see a sudden rise in your water bill since this fan-based unit consumes a lot of it, but for healthy living, it’s a small price to pay.


  • Outdoor temperature sensor
  • Ten-year warranty
  • Auto-mode
  • Thermostat


  • A bit noisy
  • DIY installation voids the warranty
  • High water consumption
  • Bulky

6. Aprilaire 700

Best Value For Money
TypeFan powered
Room Coverage2,100 – 4,200 sq ft
Daily Humidity Output18 Gallons
Dimensions16 x 16 x 10 inches

Last but not least, we include the Aprilaire 700 to our best home furnace humidifier reviews, as it excels in all areas. It offers around the clock efficient performance with next to no noise and little to no need for maintenance – so, you get the most value for money.

This Aprilaire furnace humidifier is a fan-based variant, so the hot air from the furnace gets pulled in to get humidified. Then it is delivered across the house through the ducts.

It delivers 18 gallons of moisture within 24 hours, so it can efficiently humidify insulated homes sized up to 4,200 square feet.

And for old homes that aren’t properly sealed, the furnace humidifier can provide 2,100 square feet worth of moisture every day. Not bad!

However, the Aprilaire 700 needs to be equipped with drainage to siphon off any hard water deposits, so mold and bacteria growth won’t be a problem. This also minimizes the chances of leaks, and the filter remains clean so it can flawlessly perform for up to a year.

Out of the box, you get a saddle, a solenoid valve, a water panel, an installation guide, and a 24 VAC transformer.

The featured digital Humidistat is easy to use, thanks to the comprehensive display screen. You can let it run 24/7, and the Humidistat will power it up when there is a change in the assigned humidity level.


  • Five-year warranty
  • Various indicators to show machine status
  • Produces less noise
  • Easy to clean and maintain


  • Provided instructions are detailed but not easily understandable by a layman

Some Negative Impacts of Dry Air

Dry climatic conditions can have a variety of ill-effect on our health and also on many of our possessions. Here are some of the many adverse effects:

  • Prolonged breathing of dry air can lead to bronchitis, asthma, and other issues such as nosebleeds, sinuses acting up, etc.
  • Dehydration
  • Itchy eyes, allergies, and skin problems
  • Mild static shocks can be felt when touching metal, shaking hands, and rubbing wool
  • Paint and wallpapers start tearing up
  • Plants and other vegetation start drying and dying
  • Animals also face similar problems as us
  • And much more!

So it would be best to use a furnace humidifier that maintains the humidity at an acceptable level, which is 30% to 50%, according to Mayo Clinic.

Here is a review of some top-notch humidifiers for sinus problems, and also for dry skin.

DIY Guide to Installing & Maintaining Furnace Humidifiers

Furnace Humidifier Installation

Wondering how to install furnace humidifier? Follow this step by step guide to the T, and you will be done at the soonest.

  1. Make the inaction where the furnace humidifier will be fitted. First, mark the area with a felt-tip, drill holes around it, and use the aviation strips to cut around the outline. Position the mounting plate and use sheet metal screws to fasten it
  2. Position the humidistat on-top of the furnace humidifier on the plenum — first, mark the holes with the felt-tip then drill in them; and then attach it to the mounting plate
  3. Refer to the provided manual, to learn how to connect the furnace and Humidistat. Connect all wires properly and then put the transformer
  4. To attach the humidifier, connect the solenoid valve to the Humidistat by using screws. Ensure that the wires are in the right place and then torque till fully tighten
  5. Now comes the part of connecting the waterline. If a saddle valve is not permissible, connect it by using a bypass-line. On the other hand, if a saddle valve is allowed, then install it to the water line then connect the water line to the furnace humidifier.

Refer to the user manual that came with your whole house furnace humidifier; all these steps will be detailed. But, it would be best to call in an expert for furnace humidifier installation.

The cost of installing a humidifier for a furnace may vary depending on the model and per the technician’s hourly rate. Still, typically, a thorough install takes two hours.

Furnace Humidifier Maintenance

In a nutshell, furnace humidifier maintenance is quite easy as it doesn’t need as much upkeep as stand-alone portable humidifiers. The primary component that runs the show is the absorbent pad or evaporator panel, so you need to ensure that it remains clean.

Typically, after prolonged usage for a month or two, the pad accumulates minerals left behind by the absorbed water. These minerals appear as whitish powder, and your job is to remove it.

Here are a few steps to ensure that your furnace humidifier functions at its best for years down the lane. But before you move forward, make sure that the HVAC system and humidifier are switched off:

  • Use a cloth along with cold water to wash away the mineral-buildup on the evaporator panel, if that doesn’t do the job, replace it with a new one.
  • On an annual basis, clean the humidifier thoroughly as there is a good chance that it is not functioning correctly owing to hard water deposits, corrosion, etc.
  • Furnace humidifier leaking is a common occurrence, and if you face it, turn it off and run a diagnosis – fix the issue – then run it again.
  • Bacteria and mold formation is quite common when water is involved. Therefore, treat the wheels and pad with anti-bacterial soaps, liquids, detergents, etc.

People Also Ask (FAQ)

Can I Add A Humidifier To An Existing Furnace?

Yes, you can. A furnace humidifier is installed to the ductwork, right beside your pre-installed furnace.

What Should I Do If My Furnace Humidifier Is Leaking?

There is a strong possibility that the furnace humidifier leaking because the drainage pipe is acting up. It may be puncher, clogged, or not connected properly. Switch off the unit and then check what the issue is and fix it. A pro tip is to put a vacuum cleaner on the pipe and feel for leaks.

Does A Furnace Mounted Humidifier Cause Mold?

Yes and no, if the machine is in perfect condition and the correct humidity levels are set and maintained, mold formation is the least of your worries. However, if it’s making more moisture than required to humidify a place, it may result in mold.

What Should Furnace Humidifier Settings Be In Winter?

The sweet spot is 30% to 50%, so you can set on that, and amend it if you notice any condensation forming on windows. That said if the outside temperature ranges between 10 to 20 degrees set the humidity levels at 25%

How Often Should You Change Your Furnace Humidifier Filter?

Do it annually, but if weather conditions are extremely dry where you reside, you may need to change it bi-annually. Here is a detailed video on how to do so.

How Much Does It Cost To Have A Furnace Humidifier Installed Professionally?

It depends on the unit you selected, but typically it can cost you as low as $200, and it can go as high as $1,000+. A steamer furnace humidifier installation may cost you more than installing other variants.


Now you know how bad dried up air is for your health and your belongings, so don’t second-guess installing a humidifier, especially if you use a furnace.

Console units are straightforward to set up, but for flawless results, you need to buy a whole house furnace humidifier.

After thorough research and inspection, we decided to go with the Aprilaire 400 as our top pick, as based on the seen results, without a doubt, this is the best furnace humidifier for mid-sized houses.