The ideal relative home humidity level is 45 percent. Achieving this ideal is a balancing act that often calls for a home humidifier.
Modern humidifiers use one of four methods to deliver moisture to a room.
Steam. Steam vaporizers create a cloud of hot steam, but they can be dangerous to use around children.
Impelling mist. An impeller smashes water into mist-sized droplets. This type of unit sometimes creates an excess of moisture and residue.
Ultrasonic vibration. Ultrasonic humidifiers use powerful sound waves to generate a layer of fine mist. Their output can be limited.
Evaporation. Evaporative humidifiers use wicking action to evaporate water and a fan to force the resulting vapor into the air.
In this review, we focus on ultrasonic and evaporative humidifiers only. We eliminated impeller-styled humidifiers from our equation because they just don't perform as well as their ultrasonic and evaporative counterparts. We eliminated steam humidifiers because they're best suited for purposes other than room humidification.
Each product was put through its paces in a controlled laboratory environment. If you need to humidify a room for health or climate-related reasons, all of these models are clearly up to the task.
Dehumidifiers pull excess moisture from the air. A humidifier’s process is much more subtle.
At our testing facility, we created a cube out of industrial plastic to simulate the conditions of an average room. Our lab techs used a heavy-duty dehumidifier to lower the cube's relative humidity. Then, we systematically allowed each of our five contenders to restore the humidity to a comfortable range.
We measured the amount of time each unit took to humidify the space. Along the way, we noted other performance issues such as noise generation and quality of water vapor.
Humidifiers have a few natural enemies, including mold, bacteria, and fungus. Standing water in the tank can become very hazardous, and excessive humidity in a room can promote mold and fungal growth.
Many manufacturers address these issues by including anti-microbial filters and chemical water treatments. Even so, it's up to the user to keep the humidifier clean and dry between uses.
We reviewed the maintenance and care sections of each contender's owners manual and performed our own maintenance routines whenever possible.
Some home humidifiers are commercial-grade workhorses capable of delivering enough vapor to rehydrate hundreds of square feet of dry air. Others are designed to humidify much smaller spaces, such as a child's room or office cubicle.
Some models have large-capacity tanks that deliver humidified air for hours at a time. Others have small tanks that require frequent refilling throughout the day.
In this section of our in-depth review, we look closely at each contender's power consumption and average run time.
When it comes to humidification, different consumers have different needs.
For some people, dry air during the colder months aggravates respiratory conditions or makes the home uncomfortable. A small, ultrasonic humidifier might be best in this situation.
For those who live in a dry climate year-round, an evaporative model that can humidify the entire house may be more appropriate.
In this section of our review, we discuss the value and price of each contender as it applies to the needs of various consumer cohorts. There's no sense in buying more humidification power than you actually need.
Bill has been a hardware store owner, locksmith, and general home repair guru for over 40 years. His ability to solve problems and repair every item in every situation is a true gift. In his spare time, you may find Bill working in his garden, tending to his perfectly manicured lawn, or riding his bike.
The Honeywell HCM-6009 is a true workhorse among home humidifiers. It's possible to reach a relative humidity level of 80 percent or higher with this unit—although the average level of comfort is around 45 percent.
As a large, evaporative-style humidifier, the Honeywell delivers mist in significant quantities. Most of this ultra-fine mist evaporates before settling onto exposed surfaces, minimizing the chance of unsightly residue.
The trade-off for the Honeywell's enhanced coverage area and ultra-fine vapor, however, is increased noise. In the BestReviews lab, we measured the decibel level at 61.4, which is quite noticeable. Considering the fact that this unit can run for about 24 consecutive hours, placement of the unit makes a big difference in the home.
Because standing water is a breeding ground for mold, bacteria, and insects, it's important to keep a humidifier clean and dry between uses. The tank(s) should be drained and the filters checked between operations. The Honeywell's dual-tank configuration features two wide openings for easy filling and cleaning.
That said, we note that transportation of the tanks could be a challenge, especially for people with mobility or weight-bearing issues. When full, the tanks are heavy; each holds about 1.7 gallons of water. The tanks are not designed to balance vertically on a flat surface, and a full tank could certainly be difficult to lift and install into the main unit.
Distilled water is highly recommended to reduce mineral deposits on exposed surfaces, but tap water could also be used in the Honeywell HCM-6009. We recommend "back flushing" the unit's anti-microbial water filters while the tanks are drying to prevent the buildup of mold, fungus, or other pathogens.
The Honeywell's $82 price could be too much for those with modest humidification needs. For those who live in dry climates and/or have respiratory issues, however, its industrial strength could make a significant difference in the entire home's humidity level.
In addition, its surprisingly low power consumption (less than 80 watts per 24 hours, as measured in our lab) and generous run time also add to the Honeywell's value.
The PuraSense Ultrasonic Humidifier uses high-frequency sound waves to break water droplets into a fine mist. The mist is then released into the air via a 360-degree positional nozzle.
The unit's total estimated coverage area is 538 square feet, so it's definitely not a whole-home humidifier. In the lab, however, we found it to be far more effective than a steam vaporizer. It's a great solution for small spaces, such as a bedroom or office cubicle.
The unit can also be used for aromatherapy, as it includes a separate compartment for essential oils. Other features we like include a sleep timer, soothing LED lights in various colors, and quiet operation.
The PuraSense is fairly easy to keep clean. The top section (with the directional nozzle) can be pulled off the main housing and cleaned with a small brush. The water tank is also accessible for a thorough wipe down, although some owners say it's a bit hard to reach.
Distilled water is not required, but very hard water could create a mineral buildup over time and reduce the PuraSense's efficiency. The unit arrives with an installed cartridge filter and two more for later use.
Based on its 1.3-liter water tank capacity, the PuraSense can operate for a max of about seven hours. Potential buyers who want to humidify 24/7 should anticipate refilling the tank several times per day. (Running the unit without water would not damage it, but mist production diminishes as the water supply runs out.)
The amount of moisture released into the air can be controlled by adjusting sound wave intensity. With numerous gradations of humidity available, we believe most people would find a setting that satisfies their needs.
Priced at $34, the versatile PuraSense makes good economic sense for those who want to humidify a small space and also might be interested in aromatherapy. We also note that the multi-color LED display can serve as a soothing night light for children or a mood enhancer for adults.
The other Honeywell product on our shortlist is the Honeywell Germ Free Cool Mist Humidifier HCM-350. Like its more powerful brother (the HCM-6009), the HCM-350 is an evaporative humidifier that uses wicking action to draw pure water from the tank.
Most dissolved solids cannot evaporate, so there is less of a chance for a white powdery buildup on exposed surfaces with this type of humidifier. But the HCM-350 goes one step further by using a UV light source to destroy over 99 percent of harmful bacteria, mold spores, viruses and fungi commonly found in standing water. As if that's not enough, it also includes a cartridge filter to strain out any solids found in tap, hard, or well water.
In terms of performance, this model is designed to provide enough cool mist to treat a medium-size room. Our own lab tests confirmed the coverage area, but we also noted a noise issue similar to the HCM-6009: both of these models can be loud during operation. On the plus side, they both provide up to 24 hours of continuous service and variable humidity level controls.
The single-tank HCM-350 is easier to refill than its dual-tank sibling. The tank stands vertically during refilling and can be easily cleaned and dried by hand, if necessary. Many of its parts are also dishwasher safe. With an impressive two-gallon capacity, however, comes an inevitable transportation issue. Some owners find the full tank too heavy to carry comfortably.
The Honeywell HCM-350 is not suited for aromatherapy or other medicinal uses. It's designed to balance the relative humidity in a medium-size room.
Although not as powerful as the HCM-6009, the HCM-350 is a robust humidifier. We note that if an enclosed room approaches its saturation point (100 percent relative humidity), a chance exists that the excess moisture could generate “rain” and cause water damage. Thankfully, the Honeywell HCM-350 offers a wide variety of humidity settings. Users should start on a lower setting and work their way up to a comfortable humidity level.
Priced at $57, the HCM-350 is a mid-range humidifier that performs far better than many of its direct competitors. Its most impressive benefits include UV light disinfection, a long-lasting cartridge filter, a stable tank design, and the capacity to generate lots of cool mist. If you have a larger work or living space that needs humidification, the reasonably priced HCM-350 by Honeywell is up for the job.
The portable Air-O-Swiss AOS 7146, equipped with international power adapters, is designed primarily for travel. However, it could easily be used as a permanent cool mist humidifier in a small room or office cubicle.
Conveniently, this unit will accept any standard 16.9-ounce water bottle. (Larger bottles could also be used as long as their threads match those of the base.) Users attach the bottle to the base, unfold the stabilizing “feet,” and position the humidifier on any flat, stable surface. A simple switch starts the mist; an LED light indicates when the water bottle is empty. There's also an automatic shutoff function.
Once empty, the water bottle can be unscrewed from the base and replaced with another (or refilled from the faucet). A metal ball at the base acts as a stopper while the unit is inverted, reducing leaks and drips. The attachment collar between the base and the water bottle is very snug by design, and some users may find the replacement process a bit challenging.
One bottle of water will allow the Air-O-Swiss to run for 5-6 hours. Over the course of 24 hours (and several refills), this quiet little machine puts out about 1.1 liters of water. That's enough to make a noticeable difference in a small room, but it's not enough to affect the relative humidity in a larger open space.
In the BestReviews lab, this humidifier performed just as well as other contenders with similar capacities. The fact that this model promoted by the manufacturer as a travel humidifier does not reflect on its ability to humidify a small space. Its $49 cost is a bit high for its size and “travel” designation, but it does have some redeeming qualities that make it worth the investment.
The Pure Enrichment Ultrasonic Cool Mist Humidifier is a tabletop unit with a multi-directional spout meant for small to medium-sized rooms. Two settings – High and Low – control how much vapor is released. On Low, one 1.5-liter tank of distilled or tap water can deliver up to 16 hours of continuous mist.
This humidifier is comparable to the others in terms of performance, but one issue that concerns us is ease of maintenance. There are internal areas of this product that are difficult to access. Those places could become a breeding ground for mildew and bacteria if left unchecked.
The unit makes occasional gurgling noises, but according to our experience with it in the lab, the sound is not bothersome. When the unit is empty, it shuts off automatically. This is a great benefit, as it prevents harmful dry runs. Users should be aware of a dry air exhaust port that needs to stay moisture-free. An optional nightlight is available.
The Pure Enrichment's entry-level price of $49 makes it an affordable alternative to high-end, ultra-powerful humidifiers. The 1.5-liter tank's run time of 16 hours appeals to overnight users. (Compare this to the six-hour run time of the Air-O-Swiss.) It may not have the versatility of an essential oil diffuser or steam vaporizer, but the Pure Enrichment can compete with humidifiers sold at three times the price.
The Honeywell HCM-6009 is a monster machine that can continuously humidify your home 24 hours a day.
With a total water capacity of 3.4 gallons stored in two convenient tanks, the Honeywell-6009 acts quickly and efficiently. There's a noise factor to consider; 61 decibels from a distance of three feet is definitely noticeable, but it's not necessarily disruptive. Potential buyers should also consider the fact that the dual tanks are a bit unbalanced and difficult to move across the floor.
But if it's raw, large-scale humidification power you crave, and you're willing to front the large initial investment, the Honeywell HCM-6009 is definitely the one to consider first.
The Pure Enrichment Ultrasonic Humidifier is a small unit for a smaller space. With a 16-hour runtime, it's perfect for an office cubicle, waiting room, or bedroom.
It's a handsome unit that looks more like a tabletop sculpture than a rigid industrial appliance. What's more, the Pure Enrichment's nightlight provides soothing illumination for children and adults who don't want complete darkness.
Other humidifiers in this price range (and higher) don't have as much capacity as the affordably priced Pure Enrichment humidifier. The unit's base and tank require diligent maintenance, but it's a small price to pay for the model's aesthetic qualities and excellent performance.