Humidifiers Product Database

AprilAire 500

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.

During my tests, the AprilAire 500 increased indoor relative humidity from an atrocious 15% to a healthy +40% 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.

I often get asked about the energy efficiency of these models, and unfortunately there's no easy answer.

An Energy Star scoping report states that, "Bypass humidifiers have extremely similar capacities and watt ratings. Therefore, the national savings estimate can’t be estimated."

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.

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.

AprilAire 600M

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 and it's 801 big brother.

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).

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.

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 AprilAire 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.

AprilAire 800

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.

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.

Honeywell HE360D

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 HE360D can combat dry air without the forced air heating system running.

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.

AprilAire 801

By now it's evident that AprilAire has a pretty strong hold on the furnace humidifier market. And really, you can't go wrong with any of their products. 

I recommend the AprilAire 801 for those who need precise humidity control, and who don't mind paying a premium price for it. 

This model is more expensive than the AprilAire 800 previously on my list, but the difference is that the 801 is what's called a modulating humidifier. 

A modulating humidifier adjusts its output based on the humidity levels and heating needs of your home, providing more precise and consistent moisture control.

Unlike standard humidifiers, which operate at fixed output levels, modulating units can vary their output in real-time, ensuring optimal humidity without over-humidifying.

This helps maintain comfort and can improve energy efficiency, as it reduces the need for constant on and off cycling.

For the AprilAire 801, this means keeping your relative humidity within 3% of your desired setting at all times.

I recommended this model to a buddy who was constantly trying to find a solution for maintaining the humidity levels of an extensive guitar collection.

Installing the AprilAire 801 has given him the peace of mind to enjoy his space without constantly monitoring the humidity levels that standalone units often require. 

Another feature I like about the 801 model is that you can customize the moisture output based on the electrical draw you choose. 

Your HVAC technician will help you decide which is best for your home and the area you live in, but in general at 120 volts it will provide 16 gallons of moisture per day. At 240 volts, it can provide a whopping 34.6 gallons per day, which is more than any other model on my list. 

Perhaps the icing on the cake is the fact that AprilAire has designed the 801 to work whether you have access to existing ductwork or not, but providing an optional ductless fan package.

Honeywell HE280

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.

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:

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!

Desert Spring

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

Still, these units are becoming extremely popular, and the market is projected to reach $2.5 billion by 2030. 

Desert Spring evens out the balance of maintenance 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 both under $250 and easy to maintain.

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

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.

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

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.