Air Purifiers vs Humidifiers vs Dehumidifiers

This article takes a look at the differences between three common home appliances: air purifiers, humidifiers, and dehumidifiers. 

These appliances are often confused with one another. It’s an easy mistake to make since all three have similar functions, and the components that make them work also share some similarities. 

In a nutshell, humidifiers and dehumidifiers are polar opposites. The former increases the relative humidity of your surroundings, while the latter decreases it. 

Air purifiers, on the other hand, work to purify the air in a room or indoor space by removing any particles, gasses, microbes, or other contaminants. 

Here, we will shine a light on the differences between all three appliances while also explaining how each one works, the situations it’s best suited for, and everything else!

We live and breathe appliances like humidifiers, so if you have any questions about humidifiers, dehumidifiers, or air purifiers, you have come to the right place. 

Keep reading to see the head-to-head comparison of humidifiers, dehumidifiers, and air purifiers. 

At a Glance

If you were looking for one winner among the three appliances in question, let us set you straight. All three of these machines have very different functions and serve different purposes. That said, while there are major differences between them, there are also some similarities. 

For one, all three work around the idea of adding or removing something from the air that surrounds you. Another commonality is the use of certain components such as vibrating mechanisms, fans, water reservoirs, and other such components. Heck, all three look pretty much the same, too, so there’s that.


  • Increase the relative humidity of your surroundings
  • Have a slight heating effect
  • Prevent dry throat
  • Prevent dry/cracked skin and lips
  • Great for dealing with dry cough
  • Come in various sizes and water capacities
  • Can cover small, medium, or large areas
  • Compact and easy to store
  • Mostly used in winter and other low-temperature scenarios
  • Available in unique, fun designs
  • Some cheap options have low-quality builds


  • Decrease the relative humidity of your surroundings
  • Ideal for use in excessive humidity
  • It can help reduce the heat caused by humidity
  • Come in various sizes and water capacities
  • Can cover small, medium, or large areas
  • Mostly used in summer and hotter climes
  • Usually larger in size
  • The design is often a bit basic

Air Purifiers

  • Used for removing contaminants in the air
  • Come in various sizes
  • It can cover both small and large spaces
  • Remove disease-causing microbes from your surroundings
  • It can be used in any weather
  • Can reduce sneezing/coughing due to irritant particles in the air
  • Do not offer any heating or cooling capabilities



When it comes to the look and feel of these three appliances, they are quite similar, with one notable exception. Specifically, while all three can usually be found in the ‘white rectangular plastic box’ variety, humidifiers also come in unique, colorful designs. These designs complement various settings and decor around a space. 

This is done to appeal to various users and to match the design of different spaces. So whether you want a humidifier for the office, the living room, baby nurseries, bedrooms, or anything else, you can find something that feels right at home. 

Air purifiers and dehumidifiers, on the other hand, almost always look a bit out of place; unless your surroundings are gray and boring, in which case, they fit right in. 


This is one of the biggest differentiators between the three appliances. Humidifiers are by far the smallest of the bunch. This compact design makes them ideal for the bookshelf, the nightstand, or the coffee table. There are, of course, larger options available as well. But generally speaking, humidifiers are small and compact. 

Dehumidifiers and air purifiers, on the other hand, tend to be a bit larger in size. Some high-capacity models are so large that they need their own dedicated nook in a room or space. 

This stark difference in size comes from the fact that dehumidifiers and air purifiers require more components, and larger components at that, to function. On the other end of the spectrum, the inside of a humidifier is much less high-tech and complicated, which facilitates the smaller footprint. 


It’s easy to understand why air purifiers and dehumidifiers cost substantially more than humidifiers. Again, the extra internal components required for these appliances to function are what make for such a noticeable difference in price. 

These components drive up manufacturing costs, which is why we regularly see dehumidifiers and air purifiers going for so much more money than humidifiers. 

That’s not to say that you can’t find high-quality dehumidifiers and air purifiers for a reasonable price. But the fact remains that while you can find a decent, low-capacity humidifier for under $25, dehumidifiers and air purifiers can easily get up into the hundreds of dollars for a good one. 

Health Benefits

If you are looking to buy any of these appliances, it’s because you want to combat the effects low/high humidity and poor air quality have on your health. 

In that regard, it is important to remember that each of these appliances will help you with a different type of health concern. Low relative humidity can cause dry skin, coughing, an itchy nose, dry skin, etc. 

Humidifiers help combat these problems by increasing the amount of water vapor in your surroundings. Similarly, if you aren’t getting enough sleep at night, low humidity might be to blame. Humidifiers to the rescue!

And if you’re getting the full eight hours but keeping your partner awake with your loud snoring, a humidifier can help lessen snoring, which is a plus. 

Dehumidifiers, on the other hand, reduce the relative humidity of a given space. This is great for very humid climates, where the high water vapor content of air can cause breathlessness and also increase the ambient temperature. 

By running a dehumidifier, you can remove the excess water vapor in the air, making it a lot easier to breathe. 

Interestingly, dehumidifiers have another health benefit that also doubles as a pro for your house. High humidity can cause paint and wallpaper to start peeling, in addition to making wood floors and fixtures expand. 

Peeling paint can emit irritant particles into the air, which can result in sneezing, allergic reactions, and a host of respiratory problems. All of these problems can be dealt with using a dehumidifier. 

Finally, air purifiers are the MVP when it comes to providing health benefits. A high-quality air purifier actively cleans the air around you. It does so by removing microbes, bacteria, irritant particles, dust, pollen, and even mold. 

This is especially advantageous for places that have poor air quality. If you live close to an industrial area, the air quality is probably lower than usual, which might necessitate using an air purifier. 

Heating/Cooling Effect

When it comes to humidifiers and dehumidifiers, you can only really use them in very specific weather conditions. For example, a humidifier is usually used in cold weather, when the air is dry. Sure, you can use it in warmer, dry weather as well, but the primary use is in the winter months. 

Dehumidifiers are most popular in the hot, sticky times of the year when the excess water vapor can be almost unbearable. 

The thing to note is that both humidifiers and dehumidifiers can actually help make the temperature a bit more comfortable. This is because humidity and ambient temperature are directly proportional. That means the higher the humidity, the warmer it feels, and vice versa. 

Put simply, humidifiers help warm a space, whereas dehumidifiers help cool it down. Now, don’t expect either appliance to take the place of a dedicated air conditioner or furnace. The idea is that both of these appliances supplement those things. 

Conversely, air purifiers don’t have an appreciable effect on the ambient temperature. They only really work to clean and purify the air. The obvious benefit of this is that you can use air purifiers in any weather, hot or cold. 


This is a hard feature to compare, given the plethora of options that different manufacturers offer for each appliance. Still, we think humidifiers have a slight edge over the competition. This is because most humidifier designs are so simple that there really isn’t much that can go wrong with them. 

We’re not trying to rag on dehumidifiers or air purifiers, but the fact is that those appliances have slightly more complicated designs, and the functions they’re designed to perform are more intensive. Naturally, this increases the chances of things breaking, components failing or having technical issues. 

Most modern designs are actually very reliable, and you shouldn’t worry too much about buying a lemon. Still, it is good to do your research and find an air purifier, humidifier, or dehumidifier that won’t give you too much trouble. 

Air Purifiers vs. Humidifiers vs. Dehumidifiers: The Winner

Like we said at the beginning, there isn’t going to be one winner among these three appliances. All three serve different purposes, and you may even need all three at different times of the year. 

Many people believe that air purifiers are the most beneficial from a health standpoint. And while we sing air purifiers’ praises, the fact is that all three appliances have massive health benefits in their own right. 

Another point of contention is the ‘bang for your buck’ each appliance provides. Again, there’s no clear winner here, as all three have different functions, capabilities, and use cases. Humidifiers may be relatively inexpensive, but they cannot do what a dehumidifier or air purifier is designed to do, and vice versa. 

Really, the takeaway from this article should be that no matter which of the three you need to get, it should be a high-quality appliance that is built to perform and last. And if you need any help figuring out the perfect one for you, check out our buying guides for the best of the best.


Shawn Willis is all about humidifiers. After working for some of the biggest names in the industry, he started HumidifierGuys with Scott Dawson. Now, the dynamic duo helps others figure out what they need in their next humidifier.

Shawn is an avid sports fan, motorcycle enthusiast, and has two dogs named Whiskey and Boba.