Do you find yourself coughing and sniffling a lot in the colder months? This may be because of the low humidity in the air.
Furnace humidifiers can be life-savers in the cold, dry winter — especially if you live in a particularly dry climate. The dry air can be highly irritating to your skin and can even make breathing uncomfortable. This could lead to all sorts of respiratory problems (1).
The best furnace humidifier adds moisture to the air that’s already being heated in your home. You just simply attach it to your home’s central heating, ventilation, and air conditioning (HVAC) system.
- Excellent output
- Easy installation
- Small & lightweight
- Built-in humidistat
- Easy clean-up
- Multiple fan settings
- Affordable
- Programmable settings
- Water panel indicator
- Automatic control
- Easy installation
- Powerful performance
- Thermal fan interlock
- Auto-flush
- Chlorine removal filter
Why You Need a Furnace Humidifier
Cost-Effective
Furnace humidifiers are better than portable humidifiers because of their ability to diffuse moisture throughout your entire house. Plus, if you have multiple rooms in your home, it would be costly to buy several small humidifiers.
Counteract Furnace Drying Effect
Furnaces produce dry-heated air. In the winter, this can be particularly harsh on your sinuses and respiratory system, leading to colds and sore throats.
What’s more, dry air affects more than just your health. It can dehydrate wood products that need moisture to “breathe.”
Furnace humidifiers, though, add moisture or humidity into the air through water vapor. Yes, they make breathing more comfortable, but they also work to hydrate your plants and wood floors.
Choosing the Best Furnace Humidifier
When searching for the best furnace humidifier, there are a variety of factors and features to take into consideration. Not all furnace humidifiers are created equally, and not all fit your family’s needs or home dimensions! Here’s what to keep an eye out for.
Type
There’s a wide range of furnace humidifiers out there, and they all work differently to increase moisture levels in the air. However, what they all have in common is that they all produce steam and push it through the HVAC ductwork. There are two main types:
Fan-Powered Furnace Humidifiers
These types of humidifiers are also known as evaporative. They work in a really simple way by exposing the furnace-heated air to water. The hot air evaporates, slowly increasing the level of moisture in your ducts.
These are among the most common humidifiers you’ll find. This is because they require minimal maintenance and are super easy to install. You’ll just have to change the filter or water panel every year.
Having a built-in fan means you’ll always have a steady air movement. This allows for more water to be consistently and efficiently evaporated, increasing the humidity.
Evaporative humidifiers have a dedicated fan and aren’t reliant on hot air convection. Therefore, you can use evaporative humidifiers while the furnace isn’t in use,
However, this ability to circulate air and increase humidity on their own makes them a bit more expensive than the bypass humidifiers.
Bypass Furnace Humidifiers
Bypass humidifiers are less expensive than evaporative humidifiers. This is in part because they don’t come with a fan or steamer. This means they’re completely dependent on your home furnace system.
They use the blower motor of the furnace. Moisture is added to the air and then recirculated to the furnace where the blower motor pushes the air into the space. This redistribution causes some of the moisture to be lost in the process.
If you get distracted or annoyed by whirring fan noises, a bypass furnace humidifier might be a better choice for you. They make minimal noise since there’s no fan. There are also fewer moving parts than an evaporative humidifier, meaning less maintenance.
Keep in Mind
Coverage
The coverage area will help you determine whether the furnace humidifier will be able to reach all areas of your home sufficiently.
When choosing a model, marry up the coverage area to your home’s area — in square feet. Subtract the square footage of any rooms that aren’t connected to your HVAC duct system.
If you have a small apartment, don’t purchase a furnace humidifier with a larger coverage area. You’ll only be wasting water and electricity.
Size and Weight
The dimensions of your furnace humidifier will depend on the size of your furnace room, basement or attic. If you have a super tiny furnace room, you don’t want to cramp an oversized furnace humidifier in there. So make sure to measure your space first.
The size and weight also impact the efficiency and coverage area. If you have a larger house, you’ll have more space to accommodate a larger humidifier.
Maximum Daily Output
This is directly related to the coverage area. A larger coverage area means higher maximum output in 24 hours.
This is measured in gallons per day. 16 gallons a day of water output is enough to cover 3,000 to 4,000 square foot areas. If you have a smaller home, look for humidifiers with even lower maximum daily output.
Also, keep in mind that more output means more energy consumption. So high-output humidifiers can increase your electricity and water bills if overused.
The Best Furnace Humidifiers of 2021
After days of extensive research, we’ve shortlisted the best furnace humidifiers. This list is a culmination of industry expert advice, our own experiences and user feedback.
1. GeneralAire 1000A Furnace Humidifier
The 1000A from GeneralAire is our favorite because of its light weight and powerful performance. It’s fan-powered, meaning it’s more efficient in evaporating water, thus creating more moisture.
Weighing only 4 pounds, you’d never think this little machine could produce a whopping 18 gallons per day. It can cover about 3,000 square feet, meaning that it’s ideal for medium-sized houses.
Our favorite thing about this furnace humidifier is its extra features. It has an automatic mode fitted with an outdoor sensor for temperature control. This means you don’t have to worry about turning it on or off, and it’ll automatically determine the moisture needed in the house.
Why We Love It
Excellent Maximum Output
Given its small size and weight, the 1000A can produce 18 gallons per day. This adequately covers most medium-sized houses.
Easy to Install
Users comment on how user-friendly the instructions are. They provide a good amount of detail about wiring the humidifier.
Take Note
Small Size and Weight
It only weighs 4 pounds and measures at 14.75 by 16 by 10 inches. This makes it ideal for even the most cramped furnace room. It also makes it easy to carry around if you need to move it.
Keep In Mind
Loud Noise
Just like other fan-powered furnace humidifiers, it does make noise. The fan makes a considerable amount of noise when it’s at full speed with the heat turned up. If your furnace is located in a furnace room or closed space, this shouldn’t be an issue.
Additional Specs
| Type | Fan-powered |
| Coverage Area | 3,000 square feet |
| Dimensions | 14.75 x 16 x 10 inches |
| Maximum Output | 18 gallons per day |
| Weight | 4 pounds |
2. Aircare MA1201 Whole-House Furnace Humidifier
This furnace humidifier adds cool moisture into the air as opposed to steam. It can humidify up to 3,600 square feet and has a maximum output of 12 gallons per day.
The best thing about this humidifier is its electronic controls and built-in humidistat. You can control the humidity through the control settings. It gives you a range between 25 and 65 percent.
The humidifier adjusts automatically to the fan speed needed to achieve the desired humidity. What’s great about the inclusion of a digital humidistat is that it maintains the humidity with digital accuracy.
Did we mention it’s really easy to clean and requires minimal maintenance? If it needs to be refilled or the filter needs to be changed, it will notify you on the indicator.
Why We Love It
Built-In Humidistat
The featured digital humidistat automatically keeps the humidity at your desired level without any manual input. It’ll automatically turn off when it’s reached the desired level, which you can set through the easy-to-use control settings.
Easy Clean-Up
This humidifier doesn’t have many moving parts — you won’t find any belts, pulleys or wheels. This makes for easy cleanup, with the bonus of an evaporative wick that effectively traps mineral deposits.
Multiple Fan Settings
You can choose from four different fan speeds to control how much humidity you want pumped out into the air. This gives you more control over your energy consumption.
Keep In Mind
Filter Replacements
The filters need to be changed often and they can be kind of pricey.
Additional Specs
| Type | Fan-powered |
| Coverage Area | 3,600 square feet |
| Dimensions | 20.5 x 21.5 x 14.5 inches |
| Maximum Output | 12 gallons per day |
| Weight | 14 pounds |
3. Aprilaire 600 Automatic Humidifier
This is the only bypass furnace heater on our list, but it’s still a high performer. Given its affordability, it still has a wide area coverage of 4,000 square feet.
It also has a maximum output of 16.8 gallons per day, so you’re not really compromising much here, even though it’s the budget pick. It’ll cover a large home and can diffuse moisture efficiently.
Our favorite thing about this humidifier is that it gives you the ability to set it and forget it. You can program your desired humidity settings by week or by day.
This programming feature is perfect if you want to conserve energy when you’re away from home. You can control the humidity level as you like — higher when you’re home and lower when you’re away.
Why We Love It
Affordability
It’s the most affordable humidifier on our list. Yet it has a great coverage area and impressive maximum output.
Programming Settings
You can program this humidifier to work around your schedule. If you want to lower it while you’re away from home, it’s totally doable. You also have the option to set it and forget it — it can run on a seven-day program that you specify.
Water Panel Change Indicator
It’s recommended that the water panel be replaced twice a year. You don’t have to worry about remembering, though. Each model comes with a helpful indicator that alerts you when it’s time for a replacement.
Keep In Mind
Requires Furnace to Always Be On
Given that it’s not fan-powered, it can’t run on its own. It requires the motor from the furnace to add humidity to the air. Users comment on how this means a higher energy consumption.
Additional Specs
| Type | Bypass |
| Coverage Area | 4,000 square feet |
| Dimensions | 15 x 10 x 16 inches |
| Maximum Output | 16.8 gallons per day |
| Weight | 11 pounds |
4. Honeywell HE300A1005
The HE300A1005 is another powerful fan-powered humidifier. It has the same maximum output as the GeneralAire 1000A at 18 gallons per day. The catch is that this humidifier can cover up to 4,000 square feet. This makes it ideal for large homes with multiple rooms.
It features HumidiPRO Digital Humidity Control technology, meaning it automatically controls the moisture level in your home. It doesn’t require any kind of manual intervention, so you can just set it and forget it. It also modulates the water intake to maintain a consistent humidity as your furnace switches on and off.
Users comment on how easy it is to install. It can be hooked up to a hot or cold water line, but it works best with hot. Keep in mind, however, that this may increase energy consumption significantly.
Why We Love It
Automatic Control
The HumidiPRO digital control allows you to leave it running all day without having to adjust it manually. You’ll have the perfect moisture level all day.
Easy to Install
This humidifier comes with an easy to follow professional installation guide. It’s a one-piece design with mounting screws around the perimeter. That means you can install it in one step rather than mounting a separate frame assembly.
Powerful Performance
This humidifier can output up to 18 gallons per day and cover 4,000 square feet. This means if you have a larger home, this product will suffice. It will even work for a medium-sized home with many rooms.
Keep In Mind
Large Size and Heavy Weight
It weighs about 16 pounds and is relatively large, with dimensions of 15.5 x 16.8 x 10.3 inches. This means it won’t fit into all furnace ducts and takes up a lot of space in small furnace rooms. Be sure you have adequate space for it.
Additional Specs
| Type | Fan-powered |
| Coverage Area | 4,000 square feet |
| Dimensions | 15.5 x 16.8 x 10.3 inches |
| Maximum Output | 18 gallons per day |
| Weight | 16.2 pounds |
5. Emerson HSP2000 Steam Furnace Humidifier
We love the HSP2000 from Emerson because of its cutting-edge technology. It features a thermal fan interlock that allows the humidifier to add moisture without heat. This means it’s energy- and money-saving since it can sense when the humidity is low but when the temperature is fine.
Another great feature is the safety cutoff switch. Its built-in overflow protection means you’ll never have to worry about a short circuit due to overcharge. It also features a flushing timer that you can manually set to flush out any excess water that wasn’t evaporated.
The Emerson also comes with a chlorine removal filter so that the moisture distributed to your home is free of toxins and harmful elements.
In terms of coverage, it’s ideal for small to medium size houses — not larger than 1,850 square feet.
Why We Love It
Thermal Fan Interlock
This humidifier doesn’t need your furnace to be to add moisture into the air. It can save you a lot on energy bills.
Humidity level isn’t necessarily tied to temperature levels — sometimes, the house is warm but filled with dry air. This unit from Emerson can provide optimal humidity control while taking home temperature into consideration.
Auto-Flush and Chlorine Removal Filter
These two features work hand in hand to make sure your filter is running mold and bacteria-free. The chlorine removal filter allows you to fill it up with tap water, while the auto-flush works every two hours and ensures there’s no mildew buildup.
Safety Cutoff Switch
The blower safety switch gives you peace of mind because you don’t have to worry about overcharging the unit due to the featured overflow protection. You can keep the humidifier running automatically without worrying about power issues. This is unique to this product only.
Keep In Mind
Difficult Installation
The unit comes with instructions as to how to install it. However, customers mention it can be difficult to install since it needs to be placed in the vertical output of the furnace. This often requires building a transition for the unit.
Unless you’re super savvy with these types of things, you’ll probably need a professional to do it for you.
Additional Specs
| Type | Fan-powered |
| Coverage Area | 1,850 square feet |
| Dimensions | 7.6 x 12.5 x 12.6 inches |
| Maximum Output | 13 gallons per day |
| Weight | 18.1 pounds |
| Product | Best | Type | Coverage Area | Dimensions | Max Output | Weight |
|---|---|---|---|---|---|---|
| GeneralAire 1000A Furnace | Overall Pick | Fan | 3,000 sq ft | 14.75 x 16 x 10″ | 18 gal/day | 4 lbs |
| Aircare MA1201 Whole-House | Cool Air | Fan | 3,600 sq ft | 20.5 x 21.5 x 14.5″ | 12 gal/day | 14 lbs |
| Aprilaire 600 Automatic | Budget Pick | Bypass | 4,000 sq ft | 15 x 10 x 16″ | 16.8 gal/day | 11 lbs |
| Honeywell HE300A1005 | Large Homes | Fan | 4,000 sq ft | 15.5 x 16.8 x 10.3″ | 18 gal/day | 16.2 lbs |
| Emerson HSP2000 Steam | Advanced Humidifier | Fan | 1,850 sq ft | 7.6 x 12.5 x 12.6″ | 13 gal/day | 18.1 lbs |
A Humidifier for Your Entire Home
Each furnace humidifier in this list delivers a powerful performance. They’re sure to fill your home with the moisture that’s much-needed in the dry winter months.
Of prime importance, however, is not choosing a model that’s too large for your home. This is easy to avoid by checking the areas covered by your HVAC system. Measure these spaces and then consult our recommended best furnace humidifiers to narrow down your options.
The manufacturers gain their products’ USP’s by adding extra bells and whistles. Good options to look for here are automatic sensors and the ability to pre-program the unit for an extended period.
