Choosing the Best Furnace Humidifier

Depending on where you live, you may find yourself with a need to add humidity into the air inside your home. Today I am going to take a close look at furnace humidifiers – from how to install a humidifier to a full list review, after you read this you will be equipped with the up-to-date market knowledge you need to ensure you pick the best furnace humidifier for your home.

When it comes to adding humidity to the air inside your home there are two ways you can do it. You can go in blind, relinquishing all control of exact humidity levels, by using portable humidifiers – or you can install a whole-house humidifier and humidistat onto the ductwork and existing HVAC system. 

The latter offers you complete control of humidity levels by way of a humidistat which acts much like a thermostat, but instead of temperature reading and adjusting, it takes and adjusts the humidity level to the exact percentage you set in your home’s air.

Is A Humidifier Right For You?

Achieving and maintaining proper humidity levels in your home is an important step to ensure the air inside your home is of the best possible quality. A whole house furnace humidifier can make it easy for you to maintain those proper humidity levels, especially if you live in a dry climate.

Dry climate homes are the homes that are in mind when these humidifiers are being created because they are more than likely going to be the homes that need more humidity in their air. By allowing the dry outside air to make your indoor air the same, you risk potential long-term health concerns and general discomfort.

If the area you live in has a humid climate then you don’t have any reason to install a humidifier in your home, this is especially true for homes located in the southern United States.

If you didn’t already know whether or not you need a humidifier, now that you do I am going to help you decide on which model is right for you by way of a comprehensive review list.

Types of Humidifiers

While the end result of a proper and comfortable level of humidity in the home remains the same, it can be achieved in different ways through the style variations of humidifiers. The main overarching discrepancy between humidifiers is that of either steam or evaporation power.

The humidity is either created by steam or through the evaporation of running or standing water, but it breaks down even further than that with a few variations of each of the types listed above.

Bypass Humidifiers

These humidifiers use a tray that collects moisture, the air in your HVAC system is then forced past the tray of water before entering your home. When the air passes over the tray the collected moisture evaporates and is then delivered into your home within the air.


This style of bypass humidifier stands to be one of the more affordable versions on the market but it can potentially lead to stricter upkeep demands.

The drum-style humidifier uses a foam pad that mounts on a spinning drum and remains submerged in the water tray. When humidity is needed the drum spins as the air passes over it so it can introduce the proper humidity levels to your home.

The reason that these specific models may require more upkeep than other models has to do with the foam pad that covers the drum. This pad can become dirty, even moldy over time and so should be regularly changed out to prevent harmful bacteria from entering your home.


These humidifiers function in much the same way that the drum-style variant does in the sense that it uses a spinning mechanism to allow water to be evaporated into the air stream. The difference is that it lacks the pad of the drum-style and instead opts for plastic discs.

The usage of plastic discs makes this the best option for a bypass humidifier.

Fan-Powered Humidifiers

This style of humidifier is recommended amongst industry experts due mainly to the increased water evaporation rate, which leads to a more efficient humidifying experience. The addition of the fan makes this possible.

The fan increases the water evaporation rate, but the water collection is similar to that of the bypass models listed above. Water is either collected in a try like a bypass humidifier or it is forced through the humidifier by a water supply line at the top and out of a drain in the bottom.

Fan-powered models do tend to be a little higher on the price scale, but they can save you money in the long run due to their increased efficiency. This model will always be recommended over a standard bypass humidifier for this reason, but they are both more than capable of getting the job done.

Steam Humidifiers

The steam humidifier acts much like a boiler heating system. It utilizes a water supply line for the intake before heating it to a boil, and in turn creating humidity in the form of steam. This is hands-down the most recommended and reliable style of humidifier on the market.

This style of humidifier supplies your home with the healthiest form of humidity and can increase the overall air quality of your home no matter the season. They require minimal upkeep which is another reason why a steam model will always be recommended above all of the formerly covered models.

Humidifier Reviews

Below I am going to highlight some of the best furnace humidifiers on the market. I am going to lay out all of the key information regarding each, from the overall cost to the mode of operation, after this review you will be able to confidently make an investment for the betterment of your home. 

1. [amazon link=”B00R3FY6KA” title=”Aprilaire 700″ /]

Aprilaire first started producing whole-house humidifiers in 1954 and has been leading the pack ever since. This fan-powered humidifier will set you back about $250, but it is effective for a massive coverage area of up to 4,200 square feet. This model takes the prize of the best whole house humidifier on the list and produces up to 18 gallons per day.

2. [amazon link=”B00R3GE0J6″ title=”Aprilaire 600″ /]

You can count on this mid-power model from Aprilaire to deliver the same effective punch as its counterparts. Similar in look, this machine covers up to 4,000 square feet and costs $175.

3. [amazon link=”B0039PR5RE” title=”Aprilaire 500″ /]

This specific model runs right around $150 which is a steal considering the reliability and longevity of the product. It is effective for up to 3,000 square feet of space. For a $25 increase, you can upgrade to the model above and cover an extra thousand square feet.

4. [amazon link=”B000DZHFDW” title=”Honeywell Home HE360A1075 HE360A” /]

Honeywell has been in the industry of improving indoor air quality since 1906, and if that’s not a testament to their dedication to the industry then this Honeywell Home humidifier should be. With infrequent maintenance required and the ability to condition the humidity levels in areas up to 4,200 sq. ft. of space, this model cant be beaten at $240.

5. [amazon link=”B074R5RZSJ” title=”Honeywell HM750A1000″ /]

Honeywell meant business when they made this monster. This is the first whole-house steam humidifier on the list, and when you pair its sleek design with its impressive humidifying capabilities it makes it a little easier to digest the asking price of $655. This choice is best for large homes.

6. [amazon link=”B003HMNOWY” title=”Emerson HFT 2100″ /]

This Emerson humidifier is one of the best values that you are going to find out there. For $150 this bypass flow-through humidifier is perfect for small to average-sized homes.

7. [amazon link=”B000WCL6R2″ title=”GeneralAire 1000A” /]

This model from GeneralAire has one of the simplest installations of any on the list. Its sleek design mounts seamlessly to the ductwork in your home. Plan on this ten-pound whole-home humidifier setting you back $270.

Humidifier Installation

For this specific how-to demonstration, I am going to be detailing the installation process of an [amazon link=”B00R3FY6KA” title=”Aprilaire model 700″ /] whole-home humidifier. The instructions that I go over are similar, if not the same, as most modern humidifier models. For model-specific instructions, you should refer to the installation manual that was provided with your humidifier.

Included Parts

Before you jump into the installation you need to open your humidifier and make sure that it comes with all of the necessary equipment to successfully install the unit. The list of equipment below is everything included with the Aprilaire 700 model – if yours is different the part may differ but they will generally be the same.

1. Template/Install Guide

The template is crucial as it eliminates all of the guesswork and allows you to cut a perfect-sized hole in your ductwork. The installation guide should be kept handy throughout the installation should you need to reference it for any reason.

2. Humidistat

The humidistat is the humidifier’s equivalent to the HVAC system’s thermostat. By utilizing a control wire the humidistat allows you specific control over the humidity levels in your home.

3. 24v Transformer

This is a crucial piece of equipment as this is the part that is used to connect the humidifier to your HVAC unit using the control wire.

4. Humidifier

The obvious, but most crucial piece of equipment for the installation is the humidifier itself.

Now that you have made sure that your new humidifier came with everything required for a successful install, you need to make sure you have all of the proper tools and additional equipment for the job.

Additional Parts

Below I am going to cover the tools and equipment that were not included with your humidifier but that you will need. I will link everything in case you come across something that you may need, and I will make sure to note if the tool or equipment is necessary.

1. [amazon link=”B00002N5KQ” title=”Metal / Tin Snips” /]

You are going to need these in order to ensure an accurate and even cutout in your ductwork. This tool is necessary for the installation and will likely see use even after the install. 

2. [amazon link=”B000JNNWQ2″ title=”Wire Stripper” /]

If you do not already have a pair of wire strippers, and you don’t feel comfortable using scissors or other undesirable and dangerous means of stripping a wire, then you should invest in a pair to simplify this and any other wiring job you may encounter in the future.

I recommend the Irwin Vise-Grip model that I have linked above. I have had this same exact pair for years and they have yet to let me down.

3. [amazon link=”B01ES0E2RE” title=”¼ inch Copper Line” /]

This is what you are going to be using to connect the water supply to the humidifier. The length of tubing you need is going to depend on the distance between your humidifier and your water tank or other water supply source.


The first thing you want to do is decide where you want to place your humidifier. Ideally, you want the humidifier to remain in close proximity to your furnace but you also want it as close as possible to a water source. If your water heater and furnace are close together that’s perfect.

Cutout Ductwork

Before you start cutting out a spot for a humidifier you need to grab the template that was included with your thermostat. Place the template on the ductwork – once it is square you can take a marker and trace the outline of the template.

With your template traced out you can get to cutting. Before you start cutting, you need to drill out the corners of the traced template. The corners allow you to maneuver the tin snips when you begin cutting the duct.

Install Humidifier Frame

Insert the frame of the humidifier into the hole in the ductwork. Once the frame is inserted you need to turn the rotatable clips on the inside to lock the frame into place.

Once the frame is mounted onto the ductwork you need to make sure that it is sealed up to prevent any wasted air. To seal the frame to the ductwork you can either use tape or a bead of caulk.

Install Water Panel

The next step is to reinstall the water panel inside the humidifier frame. You want to make sure that the drain spout is pointing towards the bottom of the humidifier.

Replace Cover/Fan

Now you want to replace the cover of the humidifier. In order to attach this particular cover/fan, you need to hook the top of the cover to the frame and then secure the bottom by snapping it into place.

Connect Water Line

Now you want to connect the ¼ in. water line to the bottom of the humidifier and whatever your water source may be.

Install Drain

Once the water line is connected you need to run the drain hose. The drain hose connects to the bottom of the humidifier and should be run to a code-approved drainage system.

Attach Lead Wires

The two lead wires coming out of the bottom of the unit are going to be used to connect to the 24v transformer and the humidistat. This is going to be what enables your system to detect the humidity levels in the air and adjust accordingly.

Plug It Up

Now that your humidifier is installed and it is just about ready to run you can go ahead and plug it up. The final set of steps is going to cover the mounting and wiring of the humidistat – once this is done your new whole-house humidifier is going to be ready for use.

Humidistat Installation

Now that your new humidifier is installed it is time to complete the final steps of the installation by wiring and mounting the humidistat.

i. Drill Sensor Hole

The humidistat comes with a sensor on the back of it that allows it to detect the humidity levels of the air passing by. In order for the sensor to work, you need to mount it downwind of the humidifier itself.

This particular model requires a ¾ in. hole to be drilled into the ductwork to allow the sensor to sit inside the duct.

ii. Mounting

Once you have the hole for the sensor drilled out you need to mount the humidistat. In order to do this, you first need to take the cover off the humidistat. Once the cover is off you can secure the humidistat to the ductwork with a couple of sheet metal screws.

iii. Wiring

Now that the humidistat is mounted you can move onto the final step which is the wiring. In order to ensure proper wiring, you need to reference the model-specific wiring guide that should have come with your humidifier.

If you are not sure about how to wire your humidifier or humidistat then it is always a good idea to hire a professional. Electricians or HVAC technicians can take on this job for you if you arent comfortable doing it yourself.


The key thing to remember before purchasing a humidifier is that there are different modes of humidification, and with each one comes slightly different maintenance requirements. While the more affordable bypass models require regular upkeep, its more costly steam-powered variant requires next to no maintenance or upkeep.

Regardless of the model you choose to purchase, the method highlighted above should get you through just about any humidifier installation. If you don’t feel comfortable installing your new humidifier yourself then don’t hesitate to consult a licensed professional to come out and ensure the job gets done right the first time.

I hope this article covered everything that you need to know before making an investment in a whole-home furnace humidifier. You can count on every one of the models reviewed above to deliver and maintain the proper humidity levels in your home.