Are you tired of waking up coughing for seemingly no reason? Or do you constantly feel sluggish, tired, and breathless when you’re around your home? A humidifier that attaches to your furnace could be just what you need!

When the air in your home is too dry, it can cause all kinds of respiratory problems for you and your family, even if you are usually fit and healthy. Your skin and nasal passages will dry out, you’ll become dehydrated and suffer from headaches, and you’ll likely get ill more often throughout the year.

A humidifier that attaches to your furnace is a great solution to these problems since it will add moisture to the air that can noticeably alleviate these symptoms. You’ll feel healthy and hydrated, and a furnace humidifier is more compact and energy-efficient than other types, so you’ll save on space as well as energy bills.

Keep reading for my home furnace humidifier reviews, or use this convenient table of contents to skip my essential buying guide.

I’ve worked as a qualified Heating, Ventilation, and Air Conditioning (HVAC) specialist for over a decade. I’ve drawn on this experience to find the best whole house furnace humidifier for you and your home that your money can buy in 2021. Read these HVAC humidifier reviews, and we’ll discover which of the top furnace humidifiers is right for you!

Furnace Humidifier Reviews

Best Overall 2021

This bypass furnace humidifier from well-trusted manufacturer Aprilaire is the digital sibling of the 500M model. Bypass humidifiers are great if you’re looking for a quiet and discreet alternative to fan-powered humidifiers. 

This humidifier comes fitted with an easy-to-use digital humidistat. This supports manual operation for when you want to completely control your home’s humidity and automatic operation, so you can input your desired settings and then get on with your day.

This Aprilaire furnace humidifier has water panels that should be replaced every humidifier season, that is, any season local to you that reaches humidity levels of 30% or less. The useful water panel indicator lets you know exactly when it needs replacing if you’re not sure.

The Aprilaire 500’s warranty is only valid when installed by a professional. This isn’t unreasonable since you’d need to have some competent skills at HVAC system installation to get it right. Just remember that it can cost you an additional $350-$450 on top of the unit itself.

This unit isn’t very effective at circulating humidified air around larger spaces of 2,500 sq ft or more. If that’s something you’re looking to do, I’d recommend taking a look at the Aprilaire 700M instead. 

Otherwise, this is a great furnace humidifier that can work effectively in a small house or apartment. It has some nice smart features that make it one of the best bypass furnace humidifiers I’ve come across. 

What We Like:

• Smart humidistat for optimum humidity
• Water panel indicator
• Convenient digital humidity control
• Quick and consistent humification for homes up to 2,500 sq ft

What We Don’t Like:

• Requires professional installation
• Not great for larger spaces

Best For Mid-Sized Homes

This whole-house evaporative humidifier doesn’t require HVAC ductwork like bypass or flow-through humidifiers. Instead, the GeneralAire 1000A uses its own fan to pull in warm air from your furnace into the unit and then circulates it back through the system. This technology is more efficient and can reduce your energy bills in the long run. 

A GFX3 digital humidistat monitors the outdoor temperature and adjusts humidity settings inside your home to ensure your home isn’t filled with condensation. If you prefer to control these settings yourself, there’s a manual mode too.

The unit is built to last and is made from robust and durable UV plastic. This means the included 10-year warranty should see it through most of its lifespan and not leave you out of pocket. That lifespan is increased by a design that ensures easy maintenance and makes the replacement of water panels quick and effortless.

Since the GeneralAire 1000A can produce 18 gallons of moisture per day, it can humidify a tightly-sealed home of up to 3,000 square feet, making it a great option if you’re looking to add humidity to a mid-sized home.

What We Like:

• Digital GFX3 humidistat balances humidity with outdoor temperature
• Manual or automatic mode for temperature compensating control
• Durable build
• Evaporator panel
• 18 gallons per day water output

What We Don’t Like:

• 10-year warranty needs a GenealAire contractor to install

Best Eco-Friendly Humidifier

This Honeywell furnace humidifier can release around 16 gallons of moisture per day, with an approximate coverage area of 3,000 sq ft, so you’re well covered if you own a mid-sized home or large apartment. 

The PerfectFLO water distribution system ensures optimal water usage, consistent humidity and is energy-efficient, low-cost, and eco-friendly. If you’re conscious of your energy usage and its impact on the environment, this is a solid model to consider. 

The included installation kit means this model can be up and running around 3 hours after getting it home and will save you the cost of having a professional do the job, which can cost about $450.

Because it is a  flow-through humidifier, this unit essentially cleans itself and requires much less maintenance than a drum or bypass home humidifier. You’re also a lot less likely to have to deal with airborne mold and spores.

If you’re looking for an environmentally friendly, energy-saving humidifier for up to 3,000 sq ft of space, I’d recommend the Honeywell HE240A.

What We Like:

• Works in homes up to 3,000 sq ft
• Flow-through design for less maintenance
• PerfectFLO water distribution tray for consistent humidity
• Easy installation
• Evaporation pad releases cleaner moisture into the air

What We Don’t Like:

• Not suited for larger homes

Best Console Humidifier

AIRCARE is a brand that specializes in HVAC systems that deliver a cool mist across your home. T Console whole-house humidifier is a high-performance model that will cool multiple rooms up to 4,000 square feet. 

That’s an impressive output given that it doesn’t need to link to your furnace ducts and requires minimal installation, but bear in mind it does mean your home needs to be open-planned to feel the benefits across the whole house. 

Simple 3-button controls are user-friendly and offer more than just a simple on/off option. The ‘humidity’ button maintains a desired relative humidity. The ‘fan’ button cycles through 4 fan speeds that determine how quickly air is circulated through the system, controlling how quickly the reservoir drains.

It’s a big, bulky unit that’s semi-portable, but you wouldn’t want it on display anywhere but the cramped furnace room since it’s made out of very cheap-looking, all-white PVC plastic. Considering that many modern humidifiers are made with aesthetics in mind, it’s a disappointing downside. 

If you’re looking at providing humidity to a single-story open plan home or an apartment, or you don’t want the hassle and cost that comes with installing the system into your ductwork, this could be a great option for you.

What We Like:

• Simple 3-button control
• Minimal cleaning
• Whole-house humidification up to 4,000 square feet
• Functional capacity for a mid-sized home

What We Don’t Like:

• Bulky and cheap-looking design
• Requires filters

Best For Large Homes

Since the Aprilaire 700M is fan-powered, it can operate without your furnace or heat pump being powered on. Fan-powered furnace humidifiers are more powerful than ducted bypass models since the fan blower motor circulates air in the system faster, producing more moisture more quickly. This is great if you’re looking to reduce your energy usage while still achieving relative humidity. 

This extra fan power ensures this unit can effectively add humidity to the air of a large whole house of up to around 4,200 square feet. That makes it a perfect option if you have 3-5 bedrooms and makes the comparatively high initial price very much worth it. 

Automatic humidity level adjustment makes sure the unit is running when humidity levels are low and switches back off once a comfortable level has been reached. You can, of course, override this automatic setting if you prefer to be in control of your humidity levels. 

This unit comes with a generous 5-year warranty that should see you well into the second half of its lifespan with professional installation. DIY installation could void your warranty, so I’d advise sticking with a professional HVAC system specialist.

What We Like:

• Built-in fan pulls heated air directly from the furnace
• Complete coverage for homes of up to 4,200 square feet
• Automatically adjusts humidity level
• Includes two season-specific water panels
• 5-year warranty

What We Don’t Like:

• Pricier than other models
• Higher water bills

Furnace Humidifier Buying Guide

Not all furnace humidifiers work in the same way, and each has its advantages and disadvantages that you’ll need to understand and consider when looking for the best one for you. 

Type

There are 3 different types of furnace humidifiers. All work with a forced-air furnace and all are effective methods of raising indoor air humidity levels in dry air and use different technology to do so.

Drum Humidifiers

Drum-style humidifiers consist of a rotating drum that is fitted with an absorbent pad. As the drum moves through the water in the reservoir, the pad absorbs the moisture. The system uses your cold air plenum to draw in air and your return air duct, and an evaporator pad to disperse moisture into the air. 

They’re 100% efficient at turning every drop of water used into dispersed humidity in your home’s air, so you’ll save money off your water bills. However, they need the furnace running to operate, and the sitting water can turn stagnant after a few days. The bacteria harbored in this case can be distributed through your home and cause flu-like illnesses.

Flow-Through Humidifiers

A flow-through humidifier also uses an absorbent pad and an evaporator pad to work. Instead of using a drum of standing water, a flow-through humidifier instead delivers a steady stream of water across the pad, which puts the unit at far less risk of bacterial contamination. No reservoir also means less maintenance. 

This design needs to be connected to a water supply and a floor drain system as well. It can mean a more complex installation, costing around $250-$300, which is double the average cost of installing a drum-type humidifier. 

Steam Humidifiers

A house-house steam humidifier, unlike evaporative humidifiers, uses electricity to turn liquid into gas. This is not only a faster way to deliver sufficient humidity into your home but can also be more precisely controlled. 

A steam humidifier is a great option for larger homes, and the fact that your furnace doesn’t need to be on for them to work means you’ll likely lower your energy bills. 

This advanced technology and increased power make them more expensive than drum or flow-through humidifiers, and the requirement for professional installation can further drive up the cost. 

Stand-Alone Humidifiers

Otherwise known as portable humidifiers or console humidifiers, these units are portable and require very little installation, but they’re also heavy and difficult to move. They need daily maintenance such as filling water tanks and cleaning, which can quite quickly become tedious. 

They can provide enough moisture for multiple rooms in a home of around 3,000 square feet, so they’re a good option for single-story homes or apartments. 

Daily Humidity Output

The humidity output of a whole-house humidifier is a standard measurement of how well it can humidify a certain amount of square footage or a number of rooms. It’s an important consideration when determining the size and type of humidifier that is best for you and your home.

Daily humidity output is measured in gallons per day, which is the amount of water the unit can produce to be distributed through your home in a 24-hour period.

How well insulated and sealed your home is can also affect the gallons per day you need. A tightly sealed home will have good insulation, draft-reducing weatherstripping, sealed air and energy leaks, and an effective vapor barrier. 

For a well-sealed home of around 1,500 square feet, you should look for a unit that delivers 3 to 6 gallons per day. A loosely sealed home of the same size would need a unit to provide 7 to 10 gallons per day, which most modern furnace humidifiers can accommodate.

Weight And Dimensions

When you’re choosing a furnace humidifier, you’ll need to consider the size of your furnace room and whether there is enough clearance space around your heating system to fit the extra unit. 

A fan-powered or steam humidifier usually weighs between just 5 and 15 lbs, but a console humidifier could weigh between 25 and 30 lbs. Bear this in mind if you’re planning to install it upstairs. 

Setup And Installation

The setup and installation of an evaporative humidifier is a relatively simple process and can be completed by anybody with some basic knowledge of HVAC systems. 

Many models come with detailed instructions on how to install them yourself, and this makes them much cheaper than steam humidifiers when it comes to installation costs.

Because they use electricity to turn hot water into hot air, steam humidifiers need to be installed by a professional HVAC expert, costing around $450. 

Maintenance Interval

A drum whole-house humidifier requires more maintenance than any other whole-house humidifier. The pad can become encrusted with minerals and sediments, while the standing water supply can become stagnant after a few days with no use. 

Untreated, the airflow through an evaporative humidifier will become restricted and less humidity will reach your air. Having this done professionally can cost between $50 and $200. 

Flow-through units require less maintenance and at less regular intervals since they do not use a standing water supply. They also act as a self-cleaning unit because of the water flow. They’ll still need basic maintenance such as cleaning or replacing the pad or water panels, but these are easy tasks that do not require a professional. 

A steam furnace-mounted humidifier needs to be professionally installed because of the electric heating element it uses but requires only the most basic routine maintenance. This only needs to be carried out around once every year, so it is very cost-effective once it’s in place.

Extra Features

Consider the extra features that you’ll find most useful in a furnace humidifier. But remember that different units come with different features, and some are unique to certain models. 

Low Water Cutoff

If the water levels in the reservoir ever drop below the heating element, this feature will automatically shut off the humidifier.

Overflow Protection

The opposite of a low water cutoff, this feature prevents overflow in the system reservoir. As steam is replaced by fresh water and the water levels inside the reservoir rise, a float valve shuts the furnace humidifier down if it goes above a certain level.

Mounting Frames

A framework that makes it even easier to install the system into existing ducting.

Corrosion Resistance 

To extend the lifespan of the furnace humidifier and prevent damaging corrosion from setting in, some models are protected by a corrosion-resistant casing.

Water Reservoir Change Indicator

When you need to empty or replace the water reservoir in a bypass humidifier or drum humidifier, this handy feature will give you a visual or audio alert.  

Automatic Control

With this feature, just set your desired humidity level, and the system will work automatically to monitor and maintain this level of moisture control.

Reversible Side Panels

These allow for either left-side or right-side installation, so the humidifier is in the best possible position to work to its full capacity.

Who Can Install My Furnace Humidifier?

All types of furnace humidifiers can technically be installed by anyone, but most models require professional installation to prevent your warranty from being voided. 

A steam furnace humidifier may require a 240volt circuit to be installed in your home since most models run on this voltage. This procedure requires professional installation and shouldn’t be attempted by anyone except the most experienced electricians.

Furnace Humidifier: Frequently Asked Questions

Are Humidifiers Bad For Your Furnace?

A furnace humidifier is designed to reduce the strain on your furnace, by using your warm air supply to distribute moisture into dry air. They’ll actually increase the longevity of your furnace rather than damaging it. 

How Much Does It Cost To Put A Humidifier On Your Furnace?

The average cost of furnace humidifier installation is around $450. The lowest you should expect to pay is about $350, and you should spend no more than $550.

How Long Do Furnace Humidifiers Last?

When properly maintained, a furnace humidifier should last around 10 years. 

What Do I Need To Install A Furnace Humidifier?

To safely install a furnace humidifier yourself, you should be able to follow installation manuals, own basic hand tools, and have the tools required for cutting sheet metal.

If you’re not sure, enlist the help of a qualified HVAC professional to avoid unsafe installation and voiding your warranty.

My Final Thoughts

After reading these reviews and the buying guide, I hope that you feel more confident when choosing the best furnace humidifier for you.

I found Aprilaire products to deliver both quality and reliability, so they’re definitely a good starting point if you’re looking to narrow down your options. The Generalaire 1000A model is perfect for supplying moist, hot air to mid-sized homes, and the AirCare MA1201 is the best portable console humidifier I found for effective humidity control. 

Remember to refer to this guide if you feel like you need more help deciding what you need and which model provides the solution to those needs. You’ll be feeling the benefits of refreshing, humid air in no time at all!