Best Furnace Humidifier: Aprilaire 500M Whole Home Humidifier

How do you pick the best whole house humidifier?

The best answer depends on your home—how it is heated and how much space you need to humidify.

The goal is to raise the humidity in your home to a 35% to 45% range . . . that’s the optimal range. The challenge? When you heat a home, the hot air naturally dries out the air. Naturally, the colder (and drier) the climate you live in, the bigger the lift for a humidifier to reach that range.

When we talk about a whole house humidifier, we aren’t referring to those small ultrasonic humidifiers designed for bedrooms or other small living space. That type holds a gallon or two of water and must be frequently refilled. These small, bedroom-style humidifiers are good solutions if you live in a small apartment or condo.

To humidify an entire home, however, requires a bigger humidifier solution. There are basically two choices: furnace-attached humidifiers (typically installed by a professional HVAC technician) and portable large-capacity humidifiers that can be moved from room to room.

If you have a forced-air furnace, then a furnace-installed humidifier is an effective solution for most homes. These evaporative-style humidifiers have wicks where water passes through, humidifying air from a furnace. Here’s a graphic on how that works:

For the best furnace-based whole house humidifier, we’d recommend Aprilaire’s 500M Whole Home Humidifier. We’ve been using an Aprilaire humidifier in our home for the past 19 years, so we can give a long-term perspective on what has worked . . . and what doesn’t. Here’s more:

What We Liked

• Simple design. Dry air comes in, humidified air goes out.

• Little maintenance. You have to change the water filter panel once a season—and it’s rather simple to do. 

• Hard or soft water = no problem. Because this is an evaporative humidifier, the type of water you have doesn’t matter . . . this model works just as well either way.

• Manual control is easy to use. You dial the humidity and it just works.

What Needs Work

• Only works up to 3000 square feet. If your house is bigger, you may need a model with higher capacity than this one. Good news: the same brand offers other models that do just that.

• Professional installation by HVAC contractor/plumber may be required. Yes, we do see some reports that do-it-yourself folks can install this by themselves . . . but it takes some experience to pull this off.

• May not be the best solution for extremely dry or cold environments. In our experience, this humidifier can raise the humidity about 10% to 15%. That works well for moderately dry climates. However, in places like where we live (Colorado), that 10% boost isn’t enough when the furnace runs constantly (think January). A steam humidifier may be a better bet for those folks.

Best Portable House Humidifier: AIRCARE EP9 800 Digital Whole-House Pedestal-Style Evaporative Humidifier

Furnace bypass humidifiers (like the Aprilaire model we discussed above) have one major drawback—they often require professional installation. And that can add hundreds of dollars to the cost. 

A more affordable solution is a portable whole house humidifier—we’d recommend AIRECARE’s model EP9 800 as a good solution. No professional installation is needed . . . and you can move it to the driest part of your house (such as a sunny room with southern exposure).  Here’s more:

What We Liked

• Works in up to 2400 square feet.

• Affordable.

• Nice look fits into most decors. The faux wood looks nicer than other models that are mostly white plastic.

• Digital read-out, with actual room humidity and desired level.

• 9 fan speeds.

• Auto-shut off when reaches desired humidity . . . or runs out of water.

• No white dust. 

• Holds 3.5 gallons of water. Depending on how dry your house is, this will last about 24-48 hours. 

What Needs Work

• Loud. At the highest setting, this unit measures 68 decibels—that’s close to a vacuum cleaner. However, on low fan speeds we think the noise is tolerable (about 58 decibels).

• Must replace the wick every 30 to 60 days. And if you have hard water, it may require even more frequent changing. That’s much more than furnace humidifiers, which only require a wick to be changed at the start of the heating system.

• Control panel lights are bright—and can’t be dimmed or turned off.

Best Budget-Friendly: AIRCARE 831000 Space-Saver, White Whole House Evaporative Humidifier

There’s no need to spend hundreds of dollars to get an effective whole house humidifier. We’d recommend AIRECARE’s model 831000 as a good solution to add humidity to a whole house, without breaking the bank. Well-made and effective, yet easier on the wallet.

This evaporative style humidifier holds a whopping six gallons of water. That enables it to humidify up to 2700 square feet of space. 

We liked the digital controls (and humidity sensor) of this model. And it worked as advertised, pumping out copious amount of moisture when we set it up in a Colorado home. For desert climates, this would be a good solution.

We also use this style humidifier when the temperature plunges under 20 degrees outside. Why? When a furnace is pumping out lots of warm air on a very cold day, the humidity in a house can drop to 20% or less. A large capacity humidifier like this model helps supplement smaller ultrasonic models, based on our experience.

What We Liked

• Large 6 gallon capacity—runs for 2-3 days before refilling (depending on how dry your house is, of course). The maker says it has a 70 hour run time on the lowest fan speed.

• 3 fan speeds.

• No need for professional installation.

• Easy to use.

• Humidistat turns the unit on or off depending on the moisture level.

• Easy to fill.

• Three speeds.

• No white dust residue.

What Needs Work

• Could be easier on the eyes. Yes, we recommend this humidifier . . . but it basically is a large white bucket with a fan on top. It’s not very attractive. If that is more of a priority, we’d go for the AIRECARE model EP9 800 reviewed earlier in this article.

• Filters must be periodically replaced. But that is true for most evaporative humidifiers. 

• Noisy. Yes, this model has three speeds—but only the lowest speed is tolerable, in our opinion. The higher speeds make the unit quite noisy. This humidifier is designed for living rooms, kitchens or other large spaces. It isn’t ideal for a bedroom.

Best Large House Humidifier: Aprilaire 700 Whole Home Humidifier

Most of the whole house humidifiers in this article work up to 3000 square feet. But what if you need to humidify a larger space? If the budget will allow, we’d recommend the Aprilaire 700 Whole Home Humidifier. 

Yes, this is a furnace bypass-style humidifier . . . and it will most likely require professional installation. But the 18 gallon capacity is 50% more capacity than the Aprilaire model 500M discussed first in this article.

Also: this model has much more sophisticated controls, with an outside sensor that lets it automatically adjust based on outside temperatures (the colder the outside air, the more a humidifier must work). Here’s more:

What We Liked

• Effective at raising humidity even in large spaces.

• Fan powered. That means this humidifier can run independent of your furnace—and pump out humidity even if the furnace isn’t running. That’s great for dry desert climates where you need humidity without heat.

• 18 gallon per day capacity. 

• Minimal maintenance. This model has a filter panel that must be replaced once a heating season . . . that’s it!

• Digital controls that adjust automatically based on outside air temperature and inside humidity.

What Needs Work

• Pricey.

• Floor drain required. 

• Most likely requires professional installation. And that can add hundreds to the final cost. The wiring is tricky, so this may not be a job for do-it-yourselfers.

• Fancier controls = more things that can break! This unit is reliable, based on our interviews with HVAC contractors and our parent readers who’ve had it installed in their homes. However, whenever there are more complicated electronics—like the automatic controller here—there is always a higher chance of something breaking down the road!

Why Trust Us

We’ve been rating and reviewing products for the home and families since 1994. We do hands-on testing—we buy the products with our own money and evaluate with an eye toward quality, ease of use and affordability. For this article, we purchased two of the humidifiers (the AIRECARE 83100 and the Aprilaire 500M) to try out. The other two models are similar in design and features, except where noted. We also interviewed HVAC contractors to their feedback on which models are most reliable. 

Here’s another key point: we don’t take money from the brands we review. No free samples, no sponsors, no “partnerships.” Our work is 100% reader-supported!