The Best Furnace Humidifier

The Best Furnace Humidifiers for Your Home

The best furnace humidifier is one that increases the comfort of your entire home. Using a furnace humidifier is an easy and effective way to maintain humidity levels in your home. It should seamlessly integrate itself with your current heating system.

In general, the colder the air is the less humidity it can hold. During winter, the air in your home dries out quickly. The outside air is cold and dry and your furnace is heating the inside air. Check out this very thorough explanation by the Physics Department at the University of Illinois Urbana-Champaign. As your furnace heats up the air in your home it dries it out the same way that a hair dryer works.

Using the shower adds humidity back into the air, but most homeowners will run an exhaust fan to get this overly humid air out of the house. If you don’t, you risk the development of mold on your bathroom ceiling or walls. Cooking adds humidity to the air, but again, most people will use a fan or air purifier to prevent cooking odors from lingering in their home. These appliances generally trap the moisture in their filters or use an exhaust vent that leaves your home.

Room humidifiers take up extra space in your home that you may not be willing to give up. They usually sit on an end table next to your couch or on your nightstand in your bedroom. Their appearance can also clash with the décor of the room where it is being used.

There’s no need to sacrifice the look of your room just to place a humidifier. Keep your phone and alarm clock accessible on your nightstand. Your furnace humidifier should stay out of sight along with your furnace.

Today we review some of the top furnace humidifier brands and a few of their benefits. Near the end of this article we give our recommendation on the best furnace humidifier and why we picked it.

Benefits of a Furnace Humidifier

One of the first things you should notice after installing a furnace humidifier is how easy it is to breathe. The membranes in your nasal passages and throat will benefit from ideal humidity levels and feel great.

After a few days you may notice your skin is needing less and less lotion. This is because your body is losing less moisture. Dry air robs your skin of the moisture it needs to stay healthy. Healthy skin protects you from infection and delays the signs of aging. Your pets will gain this same benefit. We can’t see their skin, but we can see them scratching dry and irritated skin. As they scratch they are launching massive amounts of dander and hair into the air. The healthier their skin is, the less itchiness your pet will experience. Some allergy sufferers note a significant improvement in their symptoms as a result of this.

Wooden trim, hardwood floors and custom cabinetry can suffer cracks and speedy deterioration if their environment is too dry. The same way dry air takes the moisture out of your skin, it also steals water from wooden items. The wood actually loses size as the water evaporates out. The shrinking causes cracks and flaky varnish.

Adequately humidified air also cuts down on annoying static cling in your clothes. Reduced static also cuts down on the painful shocks you get after walking across your carpet or touching electronics.

How do furnace humidifiers work?

Furnace humidifiers attach directly to your home’s ventilation system. They can attach to either the return side or the warm air supply of your furnace. Some models can do either, others require a more exact set up.

Generally humidifiers can operate with hard, mineral rich water. This will increase the amount of maintenance required though. As the water evaporates the minerals will remain on the evaporative pad or other surfaces it comes in contact with. Mineral deposits will decrease the effectiveness of any humidifier. If your home has a water softener, try to have the furnace humidifier installed so that it uses water already treated by the water softener. A setup like this may be able to cut down on some of the filter changes required to maintain your furnace humidifier.

The humidifier adds water into the air in your home by getting humidified air into the same ductwork that moves warm air around your home. Some furnace humidifiers turn water into steam and let the steam flow through as your furnace is blowing warm air. Others types use pads that absorb water and let the warm air flow through the pads. This gets water into the air by evaporation.

“The air in your home is the driest when

your furnace is working the hardest.”

Furnace humidifiers work when the furnace is running. Pairing the two together works great. When the weather is cold outside there is less moisture in the air. As your furnace runs to warm your home, your new furnace humidifier will add moisture back in. Furnace humidifiers rely on the furnace moving the air through your ductwork and vents.

Under Duct Humidifiers

These humidifiers are very similar in function and installation to other bypass furnace humidifiers. The difference is that furnace humidifiers install on the side of the ductwork in your home and under duct installs on the bottom. Furnace humidifiers that are installed on the side of the ductwork are more common however they may not be appropriate for the way the ductwork is designed in your home.

Under duct humidifiers usually have a larger profile – they stick out further from the surface they are installed on. Since they are almost exclusively installed in the basement of your home this will not really be a deciding factor in your purchase. Here’s an unappealing picture to show you the basic concept of an under duct humidifier.

Picture of how an under duct humidifier works

The main advantage of an under duct humidifier is their design that makes it so they can be installed on the bottom of your home’s duct work. A significant disadvantage to under duct humidifiers is their relative scarcity. There are not many companies that make them.

There is also a small possibility of mold or bacteria growth in under duct drum style humidifiers if you do not properly maintain them. Water sits in the pan for periods of time and has the potential to become a breeding ground for microorganisms. To prevent this, Skuttle instructs people to drain and clean the pan after the humidifying season. For most people this will be after winter when the air warms up and naturally carries more humidity.

Skuttle also makes a mechanism that automatically flushes the pan with fresh water every two hours for 10 to 30 seconds. This will greatly reduce the chances of bacteria or mold growth in the reservoir. Since new water is moving through it will also reduce mineral build up and increase the time between filter cleanings.

If there is hard water in your home there are a lot of minerals in the water. As the water evaporates the minerals are left behind and become concentrated in the reservoir. Over time these minerals collect on the sidewalls of the reservoir and harden into a rough coating. You can take the time to clean your humidifier with vinegar to remove this buildup.

Alternatively, you could use the Skuttle Automatic Flushing Timer to get fresh water into the reservoir every two hours. This lowers the concentration of minerals in the water held in the reservoir and reduces the chances of them depositing on the sides.

We were originally hesitant to write about the Skuttle Under Duct Humidifier because of very few directly competing models. We decided to include it because of the options it gives if the layout of your home’s furnace requires an under duct humidifier. The models we review further down in the article come from a larger lineup of competitive models and companies.


Furnace humidifiers and professional installation

Some manufacturer allow consumers to install their own furnace humidifiers. Of course, make sure you read through the entire installation manual before you start anything. Other manufacturers state that the warranty is voided unless the humidifier is installed by a qualified contractor.

Next we review two of the best furnace humidifiers available on the market today. We go over the pros and cons of each unit. The information here will help you decide on the best furnace humidifier for your home.

Honeywell HE360A Whole House Powered Humidifier


Manufacturer does allow the customer to install the unit and retain the warranty

Suitable for homes up to 4,200 square feet

Can be mounted on either the supply or return side of your furnace



It does need an installation kit that is sold separately – Honeywell 32005847-003 Installation Kit, Powered


Aprilaire 700 Automatic Humidifier


Designed to humidify up 4,200 square feet in tightly constructed homes

Performs quietly with simple annual maintenance


The warranty is void if installed by the customer, consider the cost of a qualified contractor before purchasing this item.



Wrapping it all up

Today we gave you a lot of information about the benefits of furnace humidifiers. We compared different models and highlighted areas where they stood out from the crowd.

And the best furnace humidifier is…

The Honeywell HE360A Whole House Powered Humidifier wins this contest.

Why Honeywell?

There are two big advantages the Honeywell HE360A provides. The first being the myriad of different compatible control units. The multiple options for control units is a very important feature. We talked about this in the beginning of this article. The best furnace humidifier is one that works with the heating system already installed in your home. You shouldn’t have separate control units for your furnace and furnace humidifier taking up an awkward amount of wall space. Honeywell solves this by making a huge number of control units to take care of many different furnaces and humidifiers.

The second advantage of the Honeywell HE360A is the option for the handy customer to install it themselves. Aprilaire requires a qualified contractor to install their unit if you want to retain the warranty. This may add several hundred dollars to your purchase. You can also have a contractor install the Honeywell if you choose to.

Both the Honeywell and Aprilaire models we reviewed today are rated for the same size home. The filters in the Honeywell need to be replaced as needed, up to four times annually. However, the Aprilaire 700 only needs annual servicing.

Remember the Skuttle!

We spent quite a bit of time today on the Skuttle interpretation of the furnace humidifier. The Skuttle 86-UD Under Duct Drum Humidifier is in it’s own class when it comes to furnace humidifiers. While it does not have the track record of Honeywell or Aprilaire the Skuttle does offer a unique solution. We dedicated some extra space to reviewing the Skuttle. There are not a lot of resources out there on it and we thought it deserved some attention.

If you need to mount it on the bottom of your duct work, the Skuttle is the best furnace humidifier for your home. Skuttle is also ok with the buyer installing the unit themselves. They have a very detailed installation manual. Please review the entire manual before starting to make sure you have everything you need.

Alternatives to Furnace Humidifiers

We also review a few other options that are suitable for humidifying your whole house here. In that article we review one other furnace humidifier and two console style humidifiers. The console style humidifiers put out enough moisture to treat your whole home. They do not require any complex installation procedures. However it will take up floor space and an outlet. Console humidifiers must also be refilled manually. Console humidifiers are most effective in a central location, which can limit your options.

4 Replies to “The Best Furnace Humidifier”

  1. I do agree with all of the ideas you’ve presented in your post. They are really convincing and will definitely work. Still, the posts are very short for beginners. Could you please extend them a bit from next time? Thanks for the post.

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