Humidifier Buying Guide

Humidifier Buying GuideDry climates, winter air, and artificial heat can lead to dry skin and irritated nasal and sinus membranes. Room humidifiers help restore moisture to dry sinuses and nasal membranes by adding moisture to the air. There are many different types of humidifiers available today, which can make it difficult to select the right one. Too often, we end up stuck with an expensive humidifier that worked for one season and then needed to be replaced. With this Humidifier Buying Guide, you start to shop smarter. Learn more about how humidifiers help, what types are available, and what features you should look for to ensure you select a model that provides you with years of consistent relief.

By restoring humidity to healthy levels, you can not only alleviate dry air symptoms, like eczema irritation, dry skin, and nighttime cough, but you can also promote a healthier environment for the wood furnishings and other parts of your home that could be damaged by dry air. Additionally, proper humidity also helps to keep the dust down, literally. When the air becomes very dry, particles, like dust, can more easily become airborne, making it more likely that you breathe them in. However, higher humidity helps to reduce their buoyancy and causes them to settle on the floor.

Among all humidifiers, there exists one basic division – cool mist or warm mist. You can choose between any number of warm mist humidifiers and cool mist humidifiers, and all do the same thing, relieve the symptoms associated with dry air. Some units, like dual mist humidifiers, are capable of producing mists at both temperatures. It’s important to note, though, that often dual mist models do NOT emit steam as hot as a standard warm mist humidifier.

If you are more concerned with how the water is released into the air, there are, again, other options. Ultrasonic, evaporative, boiler/steam, impeller, and air washers are all types of technologies/styles of humidifiers. Beyond this, there are features, warranties, initial costs, and maintenance costs to consider before purchasing. That said, with all of these options available, how do you decide which humidifier is right for you? That’s where we at Achoo Allergy come in to help you sort through this jungle of home humidifier options.

Humidifier Buying Guide – Cool Mist vs. Warm Mist Humidifiers

As the most basic division of humidifiers, there are cool mist and warm mist models. Cool mist humidifiers are typified by the lack of any type of heating during the humidifying process. Most standard room humidifiers available today are cool mist humidifiers. Warm mist humidity is generally created in one of two ways. Either the water is boiled, like in a traditional boiler-style humidifier, or the water is warmed. The latter is a common feature of dual mist ultrasonic humidifiers. Those that warm generally lose most of the heat by the time it exits the machine, and boiler-style humidifiers can often present a danger for pets or small children.

So, is one type of humidifier better than the other? This humidifier choice is largely a matter of personal preference. As Dr. Henry Bernstein confirms, “I do not have a preference between a warm or cool mist humidifier since both accomplish the same thing – getting moisture into the air.” Warm mist can be more soothing for stuffy noses and sinuses. If young children are around, the hot water and steam can be dangerous. A true warm mist humidifier can also make the air feel warmer and holds onto heat better, and warm mist humidifiers can actually help lower your utility bill during the winter by changing the heat index indoors. Simply put, the body loses heat faster when the air is dry.

In reality, either style of humidifier can actually make you feel warmer. The human body is constantly shedding moisture, and as moisture evaporates, it cools. This is also why many people refer to “dry heat” as a positive thing on a hot day. The same principles hold true for humidifiers. By putting moisture back into the air, it can help make you feel warmer by slowing the process by which the body naturally loses moisture and heat.

Humidifier Buying Guide – How Humidifiers Work

Humidifier Buying Guide - How Home Humidifiers WorkAs far as the method of getting moisture back into the air, there are four basic technologies. The most simple of these is found in evaporative humidifiers, which add moisture to the air using a fan that draws air over a wet wick. The air collects the moisture and is then dispersed throughout the room. Newer evaporative-style humidifiers are much quieter and more compact than their loud, bulky predecessors.

Evaporative humidifiers should be cleaned regularly to ensure the tank is hygienic, and this process also helps to remove any scale or sediment from hard water. Though cleaning is required, this type of humidifier can be used with any type of water – softened, hard, or distilled. Evaporative humidifiers often have the advantage of being “top-fill” models, which means you can simply refill them with a pitcher of water, often while they continue to operate. This type of model is generally available as a cool mist humidifier only. Effective and easy to operate, an evaporative humidifier doesn’t produce a visible mist like other styles we’ll discuss.

Air-O-Swiss S450 Is a Boiler Style, Warm Mist Humidifier But Won't BurnThe second type, a boiler style humidifier, does as the name implies – boils the water turning it into a very warm steam mist. Many people like this style of humidifier for a few reasons.

First, it kills germs, bacteria, and other microbes in the water. Second, many of these models have a medicine cup where you can use a vapor-style medicine, like Vicks, with the humidifier. Like evaporative humidifiers, boiler-style units can be used with any type of water. Lastly, because a boiler-style humidifier emits warm mist, it won’t cool the temperature of the room when used during the winter months and is more soothing to many people. The drawback to this model is that the steam can burn, and with small children or pets, it can possibly be a burn or fire hazard.

In place of actually boiling the water, many manufacturers have opted for a safer approach by simply preheating the water before turning it into a mist. While the moisture isn’t as warm as with models that truly boil (water coming out is generally right around 100°F), it is safer for those with small children in the home. This type of humidifier is considered a dual mist humidifier since it can emit slightly warmed and cool mist but is not a true boiler humidifier.

Close Up - Air O Swiss Brass Ultrasonic DiaphragmCurrently, the most popular style of humidifier is ultrasonic. This type uses high-frequency vibrations created by a small brass diaphragm to break water into micro-fine droplets. This cool fog of mist is then dispersed into the air via a small fan. There are a couple of advantages to this type of humidifier. First, there’s no boiled water. Second, these humidifiers are nearly silent. The only exception to this is with some less expensive models, which can, after years of use, begin to make a small amount of noise if the fan is not occasionally lubricated. Next, ultrasonic humidifiers have the highest output of all the types available. Under severely dry conditions, you can literally put more than four gallons of moisture back into the air with certain ultrasonic humidifiers. Lastly, ultrasonic vibrations kill many microbes by disrupting or destroying their cell walls.

Boneco humidifiers (also called Air-O-Swiss) are our leading brand in this category. With a variety of models, sizes, and options available, ultrasonic humidifiers dominate their product line. Pure Guardian and Boneco also make a variety of ultrasonic humidifiers. AirCare also has a few ultrasonic models available.

Ultrasonic humidifiers do have some unique features and require some maintenance. Some ultrasonic models come with silver ions embedded into the water tanks or use activated carbon or ionic silver accessories as natural antimicrobial agents. Scale from hard water can sometimes be a problem, but descaling agents or a simple mix of water and vinegar also removes this. Nearly all ultrasonic humidifiers can be equipped with a demineralization cartridge. This helps to remove hard water mineral content and prevent the build-up of scale. In terms of maintenance, like other models, regular cleaning keeps them hygienic and free of mineral scale.

Impeller humidifiers use constantly rotating discs to break the water into fine drops that enter the air. The technology behind an impeller humidifier has changed some over the years and now closely resembles evaporative humidifiers, except without the wicks. Humidifiers that use sets or an array of discs like this are also referred to as air washers. This is because the rotating discs in the air washer also capture dust and other impurities in the air, essentially “washing the air,” and using an array or set of discs increases the surface area for both cleaning the air and humidifying. Do not confuse an air washer with an air purifier. The air cleaning aspect of an air washer is nowhere near as efficient as a HEPA air purifier, but this is a small added bonus of this type of humidifier. In terms of humidifying, the effectiveness is similar to that of an evaporative unit but not quite as robust as many ultrasonic models. This type of humidifier works well with any kind of water but, like the others, does require some regular cleaning.


When you’re finished with the Humidifier Buying Guide, shop all home humidifiers, or check out one of these great humidifier resources.

Humidifier FAQs
Benefits of Home Humidification
Top Five Warm Mist Humidifiers
Top Five Cool Mist Humidifiers
Top Five Ultrasonic Humidifiers
Effects of Humidity on the Body
Humidifier Maintenance Guide
Five Things to Consider Before you Buy a Humidifier