7 Best Furnace Humidifiers For Existing Home HVAC Systems

Ile Kauppila

Written By

Ile Kauppila

Expert Reviewed By

Josh Mitchell

Last Updated On

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Buying, installing, and maintaining a whole-house furnace humidifier can be challenging, not to mention costly.

How do you know which of these seemingly similar units suits your living environment?

Let me tell you!

Based on exhaustive research, testing, and experience, I wrote this guide to help you find the best furnace humidifier for your home.

Quick Glance - My Recommendations

AprilAire 500 Whole-House Humidifier,...

AprilAire 500

My Top Pick

AprilAire 600M Whole-House Humidifier, Manual...

AprilAire 600M

Best Budget Model

GeneralAire 1000A Humidifier, 120V

GeneralAire 1000A

Top Of The Range

Ideal indoor humidity levels are vital for our health — especially if you have respiratory issues like I do.

A furnace humidifier is the best solution for increasing humidity in the whole house.

7 Furnace Mounted Humidifiers That Offer Value For Money

1. AprilAire 500

4.8

Overall Score


Energy Efficiency

5.0

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Humidifying Ability

4.5

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Value for Money

5.0

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Who Is AprilAire 500 Best For?

This AprilAire 500 bypass furnace humidifier is ideal for owners of small to medium-sized homes looking for effective, reliable, and affordable humidification.

Pros
  • Impressive performance in medium and small houses
  • Reasonable price point
  • Standard automatic controls make operation simple
  • Flexible installation with reversible design and hot/cold water compatibility
  • Long warranty (with professional mounting)
CONS
  • Not strong enough for large homes
  • Installation kit sold separately

AprilAire 500 has been, is, and will likely continue to be one of the most popular whole-house humidifiers for a long time.

This capable unit simply provides a value balance between capacity, reliability, and price that’s hard to beat.

This humidifier unit can introduce 12 gallons per day of humidity into indoor air.

Although the output capacity might seem low in comparison, it’s still plenty of moisture for small to medium-sized homes.

Case in point, this AprilAire humidifier has a rated maximum capacity of 3,600 square feet in tightly constructed newer houses.

Yet, even in an older 2,500-square-foot home, the unit was more than capable of maintaining 50% humidity (not that you really need it that high).

AprilAire 500 dimensions
During my tests, AprilAire 500 increased indoor relative humidity from an atrocious 15% to a healthy +30% in a couple of days.

It only took that long because the interior of the house had completely dried and needed to absorb the moisture.

AprilAire 500 ships standard with an automatic control panel and humidistat.

With both an outdoor temperature sensor and an indoor humidity sensor, the controller determines the ideal humidity levels on its own and activates the humidifier accordingly.

It’s a simple set-it-and-forget-it solution.

As a nice touch, AprilAire has included a ceramic coating on the moisture pads that slowly washes away during use, preventing bacterial and mold growth.

I suggest using a transparent drain tube, though, so you can make sure the melted material doesn’t clog it.

This humidifier has a couple of features that make installation simpler.

  • The unit has a reversible design, allowing you to install it upside down in case you want the bypass duct on the right-hand side.
  • This humidifiers works with both hot and cold water, although I recommend using hot water for ideal evaporation.
It's possible to mount the humidifier yourself, but I strongly suggest opting for professional installation.

The unit isn't very easy to install (partly because of the lackluster manual), and DIY installation will void its nice five-year warranty.

Hiring an HVAC professional is well worth it, though. AprilAire 500 is a solid, well-built humidifier that can serve you for years. It’s popular for a reason.

Feature

Details

Type of Humidifier

Whole House

Coverage Area

3600 square feet

Water Tank Capacity

12 gallons

Run Time

-

Weight

7.4 lbs

Dimensions (H x L x D)

13.00 x 15.63 x 10.25 inches


2. AprilAire 600M

4.7

Overall Score


Energy Efficiency

5.0

Current Progress
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Humidifying Ability

4.3

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Value for Money

4.8

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Who Is AprilAire 600M Best For?

This AprilAire 600M bypass humidifier unit is a great fit to humidify a large home on a tight budget.

Pros
  • Very strong humidification for a bypass unit
  • Affordably priced
  • Flexible positioning with reversibility and hot/cold water compatibility
  • Long warranty
CONS
  • Doesn’t come with mounting hardware
  • Self-installation voids the warranty

If the capacity of the AprilAire 500 isn’t quite enough for you, don’t fret.

The 600M model from the same company can increase humidity levels in large homes — at an even lower price.

AprilAire 600M has one of the largest coverage areas on my list, losing only to the AprilAire 800 steam unit.

That's particularly impressive, considering this model with a flow-through design has no fan to help it out.

This unit is rated for up to 5,000 square feet, assuming your home is tightly insulated.

I didn’t have a space that big to test it in, but the AprilAire 600M brought the indoor humidity to 38-40% in a 4,000-square-foot space within a few hours and steadily maintained it.

Long story short, it can humidify your home unless you live in a ginormous mansion (in which case, I doubt any humidifier could do the job on its own).

Apart from the larger coverage area, the AprilAire 600M offers much of the same as its 500 sibling.

In fact, the units are identical down to the internal electronics — the 600M is just a bit bigger and heavier.

It features a reversible design that lets you install it upside down for flexible positioning.

AprilAire 600M reversible installation

Water supply isn't an issue since the anti-mold coated water panels work with cold and hot water.

The biggest difference between the AprilAire bypass units is the control. The 600M is a manual humidifier with only an indoor sensor.

Useful Tip:

You must set the humidistat according to the outdoor temperature yourself.

That said, if you already have a smart, automated thermostat (like Nest or Ecobee), you can hook the 600M to it without extra components.

It's best to let an HVAC professional do that, though.

As with the 500, I wouldn't call the 600M easy to install, and DIY work will void the five-year warranty.

Additionally, you'll have to buy the mounting kit separately, which adds a few dozen bucks to the price.

Fortunately, the 600M is still affordable even with the added cost. If you need strong humidification but are on a budget, you can’t do much better than this.

Feature

Details

Type of Humidifier

Whole House

Coverage Area

5000 square feet

Water Tank Capacity

17 gallons

Run Time

-

Weight

8.7 lbs

Dimensions (H x L x D)

15.75 x 15.38 x 10.25 inches


3. AprilAire 800

4.7

Overall Score


Energy Efficiency

4.5

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Humidifying Ability

5.0

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Value for Money

4.5

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Who Is AprilAire 800 Best For?

This AprilAire 800 steam whole-house humidifier is excellent for any home that needs strong performance to reach optimal humidity levels, no matter the cost.

Pros
  • Extreme humidifying capacity
  • Suits homes of all sizes with multiple power options and optional fan installation
  • Comes with standard automatic controls
  • Quiet operation
  • Long warranty (when professionally installed)
CONS
  • Expensive to buy and maintain
  • Large size and heavy weight may limit positioning
  • Prone to water hammer

Do you need extreme humidifying performance for your home, no matter what it costs you?

AprilAire 800 can effectively increase the humidity level in your house regardless of how big it is.

Unlike other units on my list that rely on airflow to evaporate moisture, this steam whole-home humidifier takes a more active approach.

AprilAire 800 Steam dimensions
Steam humidifiers boil water with electricity and send the resulting steam into the living space to effectively eliminate dry air.

Thanks to this working method, the AprilAire 800 rocks the strongest humidifying capacity on my list.

It can emit 23 gallons of moisture per day to humidify homes up to 6,200 square feet.

During my tests, the unit maintained the indoor relative humidity level at an unflinching 40% in a 4,000-square-foot space.

Yet, this unit works for small homes as well, with flexible operation options. It can plug into both 240V and 110V outlets.

With the latter, the moisture output falls by roughly half, which can prevent over-humidification in small houses.

Although this unit is a furnace humidifier, the optional fan package lets you mount it even without an HVAC system.

Like the AprilAire 500, the 800 steam unit is an automatic humidifier.

Its dual sensors can monitor both outdoor temperature and the moisture level of indoor air, and it provides convenient digital control to maintain optimal humidity.

Steam units can sometimes be noisy, but this humidifier runs quietly and won’t bother you with incessant hissing and burbling.

Although this unit is relatively easy to install compared to the bypass AprilAire models, so it can be mounted as an (advanced) DIY project.

Important Tip:

Self-installation can mean waving goodbye to warranties on most models, including this.

The AprilAire 800 is also very expensive and — like the other AprilAires — doesn’t come with mounting hardware.

You must also regularly purchase new water canisters to prevent calcium buildup (as with all steam units).

In addition, I recommend spending even more money on a water hammer arrestor since this unit tends to experience water hammer damage with even average water pressures.

In the end, though, the superior humidifying capabilities are well worth the price in my books.

Feature

Details

Type of Humidifier

Whole House

Coverage Area

6200 square feet

Water Tank Capacity

23.3 gallons

Run Time

168 hours

Weight

23 lbs

Dimensions (H x L x D)

20.88 x 10.12 x 7.12 inches


4. Honeywell HE360A1075

4.6

Overall Score


Energy Efficiency

4.8

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Humidifying Ability

4.0

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Value for Money

5.0

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ho is Honeywell Home HE360A1075 Best For?

This affordable Honeywell Home HE360A1075 humidifier unit is a solid choice if you need to maintain proper humidity levels even when your furnace isn’t running.

Pros
  • Can maintain the desired humidity level even in big homes
  • First-grade humidistat with great accuracy
  • Works without a running furnace
  • Affordably priced
CONS
  • Lousy wiring instructions
  • The fan could be quieter

Fan-assisted whole-house humidifiers with a flow-through design can add moisture to your home even when your heat system isn’t running.

Honeywell Home HE360A1075 is an efficient yet reasonably affordable solution for humidifying your house.

This unit’s humidifying capabilities are in the top 3 among the humidifiers I have used.

It beats the AprilAire bypass humidifiers in capacity, pushing 18 gallons of moisture into the air ducts daily.

Honeywell HE360A1075 dimensions

Consequently, this Honeywell whole-house humidifier has a respectable 4,500-square-foot coverage area in tightly constructed houses.

I tested it in a 3,500-square-foot space, and it raised the indoor relative humidity from 25% to 40% within 24 hours. Not shabby at all.

Like the AprilAire 600, this unit comes with a standard manual controller, which requires you to change the settings according to the outside temperature.

That said, as the AprilAire, the Honeywell can wire into an existing automatic thermostat.

Consider keeping the manual controller, though, since it has an accurate and sensitive humidistat.

It might be even a bit too sensitive — small adjustments can result in big changes in relative humidity, so don’t be heavyhanded with it.

As a powered unit, the Honeywell can combat dry air without active forced air heating systems.

Of course, the fan does produce some noise and consumes more energy than simple bypass humidifiers.

Compared to bypass units, the Honey is easy to install as it doesn’t need a bypass duct.

It’s a much more feasible DIY project as you only need to cut an opening to your warm air supply and hook up the electricity and water connections.

You won’t really have to worry about the warranty, either, since the unit comes with only a one-year warranty.

With all that said, I suggest hiring a professional for the electrical connections (unless you're one yourself).

The manual's wiring instructions are… Well, I'd call them a joke, but I sure didn't laugh.

Fortunately, you can afford the electrician’s fee thanks to this unit’s low price.

Once you get the wires hooked up, you’ll have an effective and reliable whole-house furnace humidifier ready to serve you for years.

Feature

Details

Type of Humidifier

‎Evaporative

Coverage Area

4200 square feet

Water Tank Capacity

17 gallons

Run Time

24 hours

Weight

-

Dimensions (H x L x D)

15.25 x 14 x 10.5 inches


5. GeneralAire 1000A

4.3

Overall Score


Energy Efficiency

4.5

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Humidifying Ability

4.5

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Value for Money

4.0

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Who Is GeneralAire 1000A Best For?

This GeneralAire 1000A whole-house humidifier is the way to go if you’re looking for premium automated indoor air quality solutions for year-round use.

Pros
  • Excellent year-round humidity control in small to medium-sized houses
  • Swappable automatic and manual controls with accurate humidistat
  • Low fan noise
  • 10-year warranty
CONS
  • Pretty pricey unit
  • Bigger than it needs to be

Perhaps you like the idea of being able to maintain the humidity level in your home whether or not you’re running your heating system, but you’d prefer a more high-end solution.

In that case, GeneralAire 1000A is the belle of the ball.

This fan-assisted humidifier can produce 18 gallons of moisture daily, providing powerful humidity control on par with the Honeywell Home powered unit.

Its coverage area of 3,000 square feet isn’t quite as expansive as its rival’s, but I found the GeneralAire humidified the air more efficiently within its limited area.

I successfully produced a comfortable living environment with a humidity level of 40-45% in a leaky, 40-year-old, 2,000-square-foot house.

And that was with a huge wooden piano sucking up moisture in the living room.

In medium-sized and smaller homes, the GeneralAire packs a serious humidifying punch.

Unlike the Honeywell, this unit has an automatic control panel with a digital display and dual sensors for monitoring indoor and outdoor air.

The humidistat is the most accurate I encountered during my tests, beating even the Honeywell’s.

If you’re looking for extremely precise humidity control, look no further.

That said, the GeneralAire can function as a manual and automatic humidifier. If you prefer controlling this whole-house humidifier yourself, you can do it.

The GeneralAire unit is fan-powered, so it can pump moisture into your home during any season.

The fan is very quiet, and I wasn't able to hear it during normal operation unless I was specifically listening for it.

Since it doesn’t need extra ducts, the GeneralAire is reasonably easy to install.

However, I advise against doing so yourself for one reason — the 10-year warranty.

GeneralAire offers an incredible decade-long guarantee on the unit. Self-installation will void that warranty, so don't let it go to waste.

This unit is rather pricey and — like all powered models — can somewhat raise your energy bill.

It’s also a bit bulky, so it might not fit in the tightest utility closets.

Overall, however, this humidifier is a worthwhile investment for changing humidity levels all year long in medium-sized homes.

With a long warranty, you’ll have a long-lasting companion to improve your air quality.

Feature

Details

Type of Humidifier

Whole House

Coverage Area

3000 square feet

Water Tank Capacity

18 gallons

Run Time

8 hours

Weight

15 lbs

Dimensions (H x L x D)

16.50 x 16 x 10.5 inches


6. Honeywell HE280 - Easiest Installation

4.2

Overall Score


Energy Efficiency

4.0

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Humidifying Ability

4.0

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Value for Money

4.5

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Who Is Honeywell HE280 Best For?

This Honeywell HE280 bypass whole-house furnace humidifier is the best choice to start humidifying your home quickly with simple installation.

Pros
  • Simpler installation process than with comparable units
  • Good humidity output, even for large spaces
  • Well-designed water distribution system prolongs water panel life
  • Box includes installation hardware
  • Reasonably priced
CONS
  • Replacement parts are expensive and hard to find
  • Heavy for a bypass unit

A furnace humidifier can really contribute to good air quality in your home, but do they all have to be so difficult to install?

No, they don’t, and Honeywell HE280 is proof of that.

This unit has an unpowered flow-through design, so you will need to install a bypass channel from the return air duct to the warm air supply side.

However, you can avoid possibly the most complex part — wiring.

The HE280 has a damper air pressure switch that activates the unit when it senses flowing air.

You only need to wire the humidifier to the manual humidistat.

That said, you absolutely can hook it up to your forced air furnace, too, if you'd prefer.

Another thing that makes this unit easy to install is that it includes a mounting kit, unlike most other units on my list. 

Honeywell HE280 humidistat

The installation manual is also nicely detailed (as far as whole-house humidifier manuals go).

This unit has a daily moisture output of 17 gallons, matching the AprilAire 600.

The coverage area is on par as well — I was able to keep a 2,500-square-foot, two-story home well-humidified and even raised relative humidity by 10% in a maximum rated 4,000-square-foot house.

Another thing I appreciate about this unit is that it needs minimal maintenance.

The machine distributes water more evenly across the water panel than others I reviewed, which reduces mineral deposits and helps the moisture pad last longer.

I want to give one word of caution, though:

  • Due to its self-contained damper pressure switch, this unit uses a DC solenoid valve instead of an AC solenoid found on other models on my list.
  • The DC valves are much more expensive and difficult to find if yours breaks.

As such, I recommend installing a scale filter between the water supply and the valve.

You can afford this extra part as the humidifier itself is fairly reasonably priced.

Granted, installing the extra filter complicates the installation process a bit. Luckily, this unit is so easily mounted that it won’t matter much!

Feature

Details

Type of Humidifier

Whole House

Coverage Area

4000 square feet

Water Tank Capacity

17 gallons

Run Time

24 hours

Weight

14.2 lbs

Dimensions (H x L x D)

18.5 x 16.25 x 9.75 inches


7. Desert Spring

Best Drum Humidifier

4.3

Overall Score


Energy Efficiency

4.3

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Humidifying Ability

4.5

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Value for Money

4.0

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Who Is Desert Spring Best For?

This unique Desert Spring rotating disc humidifier is an excellent option for those who want the efficiency of a drum humidifier without the extensive maintenance needs.

Pros
  • Effective and reliable performance in medium-sized homes
  • Straightforward and cheap to maintain
  • Quiet operation for its type
  • Compact and lightweight
  • Optional auto-flush system prevents stagnant water accumulation
CONS
  • Not suitable for very large homes

Drum humidifiers can provide more efficient humidity than bypass models but generally require more extensive maintenance.

Desert Spring evens out the balance with its unique rotating disc configuration.

Instead of relying on a rotating water panel that gets easily clogged with minerals and bacteria, Desert Spring draws water from the water reservoir with flat plastic discs.

Heated air blowing over them evaporates the water and pushes it into your home through the ductwork.

This operating principle gives Desert Spring a 14-gallon daily moisture output and a 3,200-square-foot maximum coverage area.

However, I found the actual performance to be above the rated capacity.

Even in a 3,500-square-foot house, I had no issues keeping the relative humidity levels at a consistent 40%.

This whole-house humidifier punches above its rating.

Due to the solid plastic construction and no water panel, Desert Spring is cheap and easy to maintain.

It will eventually develop mineral buildup, but you can simply wash and scrape it off without buying replacement filters.

Useful Note:

While drum humidifiers are more efficient at dispersing humidity and cheaper to operate, they require more maintenance.

If you'd like to simplify maintenance, you can invest in the optional auto-flush system that drains the reservoir at set intervals.

Flushing the reservoir prevents mineral buildup, mold, and bacterial growth, which can help control asthma and allergy symptoms.

Desert Spring also has a transparent cover, so it's easy to see when the discs need a wipe with a quick glance.

The ease of maintenance and solid construction make this a very durable unit (as long as you remember to keep it clean).

This humidifier model has actually been on the market for close to two decades.

Although it’s received some updates, the basic structure has remained unchanged. Why reinvent a wheel that just works?

As a final highlight, Desert Spring is very quiet for a drum humidifier. It's also compact and lightweight, fitting in a small utility closet.

Apart from not having the output to humidify indoor air in huge mansions, there’s little about Desert Spring not to like.

It maintains healthy whole-house humidity levels without issues — what more would you want?

Feature

Details

Type of Humidifier

Rotary Disc

Coverage Area

3200 sq.ft.

Water Tank Capacity

NA

Run Time

NA

Weight

12 lbs

Dimensions (H x L x D)

11 x 12 x 12 (inches)


Comparing Furnace Humidifiers For Homeowners

Preview

Name

Rating

Type of Humidifier

Coverage Area

Price

AprilAire 500 Whole-House Humidifier,...

AprilAire 500

4.8

Whole House

3600

sq ft

AprilAire 600M Whole-House Humidifier, Manual...

AprilAire 600M

4.7

Whole House

5000

sq ft

Aprilaire 800

AprilAire 800

4.7

Whole House

6200

sq ft

Honeywell Home HE360A1075 HE360A Whole House...

Honeywell HE360A1075

4.6

‎Evaporative

4200

sq ft

GeneralAire 1000A Humidifier, 120V

GeneralAire 1000A

4.3

Whole House

3000

sq ft

Honeywell Home HE280A Whole House Humidifier,...

Honeywell HE280

4.2

Whole House

4000

sq ft

Desert Spring

Desert Spring

4.3

Rotary Disc

3200

sq ft

Factors To Consider When Choosing A Furnace Humidifier

It can be difficult (not to mention expensive) to swap out an unsuitable furnace humidifier.

You should think carefully about what you want and need from your unit before making a purchase.

Below is my breakdown of the key features and factors to remember while looking for the best furnace humidifier for your home.

Pick The Right Humidifier Type (Bypass Vs Steam)

Consider the pros and cons of each furnace humidifier type and choose one that fits your needs.

There are multiple different types of furnace humidifies, with the only connecting feature sometimes being that they attach to your heating ducts.

Here’s my brief summary of each type’s advantages and potential downsides:

  • Bypass Humidifiers
    A bypass humidifier (also called a flow-through or whole-home evaporative humidifier) relies on the flow of heated air passing through the water panel to evaporate moisture. They can be the cheapest type to buy and run but require installing an extra duct and can't function without a running furnace.
  • Powered Humidifiers
    Powered humidifiers are bypass units with fans blowing through the moisture pad. As such, they don't need any additional ducts and can run even when the HVAC system is turned off, but they do consume electricity, which you have to pay for.
  • Drum Humidifiers
    Drum models have a water reservoir a rotating moisture pad dips into. These humidifiers are typically much more effective than bypass ones. Still, they require more maintenance as the water in the reservoir can get stagnant and/or cause excessive mineral buildup.
  • Steam Humidifiers
    Instead of relying on airflow to evaporate water, steam units boil water with electricity and emit warm water vapor into the ducts. They are the most effective humidifier option and can function independently, but they are the most expensive to buy, run, and maintain.

Match The Coverage Area To Your Home's Square Footage

I recommend carefully measuring your home’s total square footage and buying a humidifier with the closest possible coverage area.
humidifier sqft coverage

It's crucial to match your humidifier's capacity as closely to your home's size as possible.

An underpowered humidifier can't raise humidity levels effectively, and you'll continue suffering from dry skin and air.

On the other hand, an oversized humidifier can increase humidity levels too much, resulting in mold, bacterial, and dust mite infestations that can cause serious respiratory infections.[1]

Choose Easy-To-Install Units (Or Hire A Professional)

I suggest choosing a unit that doesn't require additional ducts and comes with included installation hardware.

Hooking up any furnace humidifier is an advanced DIY project, but some key features can make it easier.

If you're not an expert contractor, choose a fan or steam unit that doesn't require installing extra ductwork.

If you choose a bypass unit, look for humidifiers with a reversible design (like AprilAire 500) to run the additional duct into either side of the unit.

It’s also worth choosing a humidifier that comes with all the hardware you need so you can be sure the parts match it.

And remember — it’s cheaper to hire a professional than replace messed-up ductwork.

Pay Attention To Maintenance Needs

Try to find a humidifier that lets you replace the moisture pad and clean the unit without any tools.

Every humidifier needs regular maintenance at least once per season, whether it’s replacing moisture pads or canisters or cleaning water reservoirs.

Pick a unit you can open without tools (such as Desert Spring) to make maintenance quicker and easier.

Save Money With Good Energy Efficiency

Pay attention to how much energy a humidifier consumes to ensure your energy bills don’t take off to the skies.

If you buy a fan-powered, steam, or drum humidifier, check the unit’s energy consumption before you buy it.

Try to choose a unit with the lowest power drain to save money. With steam humidifiers, also pay attention to whether they need a 240V or 110V outlet.

Bypass models can offer you the highest energy efficiency as they only need to power their sensors and notification lights.

Yet, even a powered humidifier can actually save you money in heating bills since well-humidifier air feels warmer![2]

Choose A Unit That Doesn’t Waste Water

I recommend choosing a humidifier with the lowest possible water consumption and installing a ball valve to the water feed.

All humidifiers need water to produce moisture, consuming anywhere between 1.5 to 12 gallons per day.

Steam and drum humidifiers are the most water-efficient as they use up all the water they consume.

If you notice your bypass or fan unit wasting a lot of water, I recommend replacing the supplied saddle valve with a ball valve.

The saddle valves are very loose by design to accommodate homes with low water pressures, but they can let excess water into the humidifier.

A ball valve allows you to control the water flow more accurately.

Choose Smaller And Lighter If Possible

Purchase a humidifier that’s as small and light as possible to make installing it easier.

A humidifier’s physical size won’t affect its efficiency as long as its capacity covers your entire home — but a lighter unit is always easier to install.

It’s also much simpler to fit a compact, thin humidifier into your utility closet or room if you don’t have a lot of available space.

Make Sure The Unit Is Efficient

Compare the humidifier’s daily moisture output to the size of your home to find a unit that’s efficient enough for your needs.

What are the Optimal Humidity Levels
Humidifier capacity is measured in gallons of moisture they can produce daily. A capacity of 12 gallons/day is sufficient for a roughly 3,000-square-foot home.

However, the actual efficiency depends on how tightly built and well-insulated your home is.[3]


How We Review & Rank Our Product List

At Air Conditioner Lab, our team follows a similar process when evaluating all products reviews before formulating our final lists for readers.

We begin by gathering data sources directly from brands, e-commerce platforms, online retailers and press releases.

These are then added to a master file we use to compare features specifications from all humidifier models. You can access this Humidifier Sheet Here.

Next, we narrow down all the products on the market by evaluating user reviews, ratings and feedback from a wide variety of online and in-person sources.

Our team then discusses and co-ordinates our first hand experiences using these products, as well as gather independent opinions and feedback through Youtube and customer reviews.

Furnace Vs Portable Humidifiers Explained

When looking for a humidifying solution for your home, the first choice you often have is picking between a furnace and a portable humidifier.

These two humidifier types work quite differently.

Here is my breakdown of their most significant differences, with the obvious being that furnace humidifiers will benefit your entire home, unlike portable humidifiers that only benefit the room they are in.

 

Furnace

Portable

Coverage Area

Whole House

Single Room

Portability

Permanent Installation

Easily Portable

Maintenance

1-2 Times Per Season

Daily

Ease of Installation

Challenging

Easy

Energy Consumption

Low

Medium

Noise

Low

Low To High

Lifetime Cost

Lower

Higher

Appearance

Out Of Sight

Possibly Intrusive

Is It Possible To DIY Install Furnace Humidifiers?

It’s perfectly possible to self-install a humidifier into an existing furnace, but the process can be challenging depending on the unit.

The precise installation process depends on your humidifier’s type and model. However, the basic steps are generally as follows:

  • Measure and cut a hole into either the supply duct or return air duct (installing on the supply side will be more effective).
  • Fix the unit to the air duct.
  • Cut holes and connect bypass ductwork (if you have a bypass or drum humidifier).
  • Tap a water supply line and install the necessary valves.
  • Connect the water line to the humidifier.
  • Connect electrical wires according to your humidifier’s and humidistat’s wiring instructions.

Important Note:

Note that this is a greatly simplified description, and the precise steps you need to take may be different.

Additionally, it's often possible to install or wire one humidifier in multiple ways.

Always carefully consult your humidifier's installation manual before doing any work.

Frankly, self-installing a furnace humidifier is generally involved enough that I would only recommend it if you work as an engineer or building contractor.

Hiring a professional will cost you some money. However, it's still likely cheaper than replacing ruined air ducts or electrical wiring in your home.


Steps To Maintaining Furnace Humidifiers

All furnace humidifiers require ongoing maintenance.

The most common (and easiest, fortunately) thing you must do is change the moisture pad or steam humidifier canister.

The process depends on your unit, but the basic steps are:

  • Turn the humidifier off.
  • Open the front or top panel.
  • Remove the old moisture pad or canister.
  • Insert the replacement pad/canister.
  • Close the humidifier and restart it.
how often to change evaporative humidifier filters

You should replace the humidifier filter at least once a year before the heating season, but you may have to do it more often, depending on the water hardness and your particular unit.

It's a good practice to check the filter (or the maintenance warning light) once a month.

Drum humidifiers are a bit more involved, as their pads will likely require monthly replacements.

You should thoroughly clean and disinfect their reservoirs when you change the pad to keep mold from growing in them.

Finally, if your humidifier is leaking water, the water line may be feeding too much water to the pad.

As I mentioned earlier, the best solution is to install a ball valve to the water line so you can control the flow more precisely.


Frequently Asked Questions

How Long Do Furnace Humidifiers Last?

Furnace humidifiers generally last for 10 years or longer. The ultimate lifespan may vary depending on their type and how well you maintain them,

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

Adding a furnace humidifier can cost anywhere between a couple hundred and a couple thousand dollars. The units themselves can be quite affordable, but installation costs may add to the price.

Do Humidifiers on Furnaces Cause Mold?

A furnace humidifier can cause mold if you let it raise the humidity level too high (above 45%). I recommend investing in a reliable hygrometer to monitor and maintain optimum humidity levels.

What Should a Furnace Humidifier Be Set at in Winter?

In winter, start by setting your furnace humidifier to 30 percent humidity, which is the low end of the recommended humidity levels indoors. You can then easily adjust the humidity up or down.[4]

Which Furnace Humidifier Should You Buy?

Armed with my guide, you can start shopping for the best whole-house humidifiers that attach to your home furnace.

You now know how to compare the key features that matter to you. That said, I do have a couple of personal recommendations for you.

The AprilAire 600 bypass humidifier is the way to go if you need strong but budget-friendly humidification.

Meanwhile, AprilAire 800 is an ultra-strong, high-end humidifier for the biggest homes.

My #1 Recommendation
AprilAire 500

  • Impressive performance in medium and small houses
  • Reasonable price point
  • Flexible installation with reversible design and hot/cold water compatibility
  • Long warranty (with professional mounting)

References: 

  1. https://www.healthline.com/health/humidity-and-asthma
  2. https://www.just-humidifiers.com/humidification-energy.php
  3. https://www.just-humidifiers.com/humidifier-sizing.php
  4. https://www.epa.gov/mold/mold-course-chapter-2
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Ile Kauppila

MA Multimedia Journalism / BA English Philology

Ile Kauppila
Ile Kauppila is a globetrotting writer and editor living in Virginia. Ile holds an MA degree in Multimedia Journalism and a BA in English Philology. Ile has written for a variety of home, HVAC, and energy-related websites and publications. He has covered HVAC solutions, insulation, and energy-efficient construction, automotive AC systems for multiple auto dealerships and garages.

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