Humidifier Versus Dehumidifier: What’s The Difference?

While we blindly blame various seasons for skin issues, they are merely the results of different moisture levels in the air and can be easily controlled by appliances like humidifiers and dehumidifiers. Knowing about the humidifier versus dehumidifier would help you to decide which one will suit your house the best.

A humidifier makes the air more humid by adding moisture. In contrast, a dehumidifier removes moisture from the air and makes the atmosphere less humid.

Both can be extremely helpful but in different scenarios. And you must understand which one to use in a specific situation.

Give this a read to learn everything you need about the differences between humidifiers and dehumidifiers. You’ll also learn which one will be suitable in what situation.

Humidifiers vs. Dehumidifiers: How Do They Differ?

Some of you might be well familiar with both of these appliances, while others might not. So, I have provided a simple overview below for both of these appliances to better manifest their differences and working mechanisms.

  • Humidifier

The mechanism of a humidifier is very simple; it vaporizes or disintegrates the water from the water tank and adds it to the atmosphere.

Humidifiers generate heat or energy waves from electricity and then use them to disintegrate and disperse the water.  

Depending on the working mechanism, humidifiers can be divided into two categories: cool mist humidifiers and warm mist humidifiers.

Cool mist humidifiers use some sort of energy waves to create droplets of water. Then it disperses them into the air.

Since there is no heating involved, the name often makes people wonder if a cool mist humidifier makes room cold. Well, it does create a chilly effect in the room but doesn’t lower the room temperature like an AC unit.

In contrast, a warm mist humidifier uses heat to vaporize the water and then mixes the vapor into the atmosphere. This type of humidifier is relatively less safe as excessive heat is involved in the process.   

  • Dehumidifier

If you find yourself constantly asking, “why is my house so humid?” Then a dehumidifier is what you need.

A dehumidifier takes warm and moist air as input and then absorbs the moisture from it via cooling or using some absorbent material.

From the working mechanism perspective, AC units are dehumidifiers too, as they significantly decrease the moisture in the atmosphere.  

Units that use some sort of absorber material to dehumidify are also quite prevalent in the market. They use a fan to draw in warm and moist air and then run it over the absorbent. This way, dry and cool air comes out the other side.  

You can compare dehumidifiers by their efficiency and the ‘water removed per day’ rating. ‘Water removed per day’ indicates the amount of water in liters or pints that is removed by a dehumidifier after a continuous 24-hour runtime.

The larger the machine, the higher the WRPD rating will be. Efficiency is also an important measurement to look out for because it directly concerns consumed power.

What Is the Appropriate Humidity Level for Households?

Humidity over and below the recommended level can be inimical to you and your home. The more extreme the humidity level reaches, the more harmful it will be.

Summer is mostly a humid season. And the moisture in the atmosphere peaks during a rainy day. But how much humidity a house captures depends mostly on the design of the house and the location.

If your house doesn’t get proper air circulation and sunlight during a good portion of the day, moisture is likely to build up in the air.

Also, if your house is situated near a huge water body, like a large lake or a river, the atmosphere inside and around your house will be very humid.     

In contrast, during cold winter days, the atmosphere typically becomes arid. The moisture in the air is quite susceptible to dropping below the safety level during this time.

However, the humidity level is determined by relative humidity (RH). It’s a percentage measurement of available vapor content in the air of a certain space concerning the saturation vapor content.

It means if a certain place has an RH level of 100%, the air of that place has reached the peak moisture level possible. Inside our households, a 30-50% RH level is tolerable, especially in rooms where we spend most of our time.

More or less moisture than this recommended level warrants the use of a humidifier or dehumidifier. Kitchens, basements, and such rooms contain more moisture than any other. So, you should be extra careful about these.

How Does the Humidity Level Affect You?

There are plenty of harmful effects of unsafe humidity levels. Let’s take a look at some of the most prominent ones.

  • Health Effects

Humidity levels in your home affect your health both directly and indirectly. A cold, arid atmosphere causes ashy and cracked skin, chapped lips, eye irritation, and many other issues.

Ashy and cracked skins are way more vulnerable to damage and infection. Cold, dry air also aggravates respiratory conditions like asthma, chest congestion, and sinus congestion.

In contrast, too much moisture in the air allows the growth of various harmful viruses, bacteria, and fungi. These microbes can be responsible for various types of ailments and irritations.       

  • Discomfort

Both humid air and dry air can be the causes of extreme discomfort. As water is a good holder of heat, humid air tends to trap a lot of it. Hence, the more moisture the air has, the more heat it can trap.

This excess heat keeps making you feel hot and sweat profusely. As the air is already full of moisture, the sweat hardly dries off your body. This combination of events can make you feel extremely uncomfortable.    

On the other hand, cold, dry air makes your skin ashy and itchy and your lips chapped. Chapped lips often bleed due to tears in the lip skin. Moreover, dry air also tends to dry up your eyes, making them red and itchy.

  • Effects on Your Home

Besides having various effects on your health, humidity can affect various aspects of your house. As I said earlier, too much moisture in the air can turn out to be a safe haven for harmful bacteria and fungus infestation.

A house that is constantly exposed to high humidity is prone to heavy mold infestation. Mold infestation not only hampers your health but also deteriorates the integrity of the building structure.

Lack of moisture can have various destructing effects as well. Dry, arid air cause cracks and breaks in wood beams, leather furniture, and wall plaster.

How to Measure the Humidity Level Inside Your Home

Do I Need a Humidifier or a Dehumidifier? To answer this question, you’ll need to find out the humidity level in your house first. Let’s take a look at some easy ways to determine the humidity level inside your home.

  • Using Appliances

You’ll get the most accurate value of RH by using a simple hygrometer. Hygrometers are quite cheap and can be used against air, soil, and confined spaces.

If you want something advanced, I’ll suggest getting a humidistat or hygrostat. A humidistat constantly checks the moisture indoors and turns on the attached humidifier if the moisture drops too low.

Sadly, humidistats don’t come with attached dehumidifiers, so you’ll have to buy one separately.    

  • Using Ice Cubes

If you don’t wish to spend money on a hygrostat or a hygrometer, you can get a rough assumption of humidity using only ice cubes. All you’ll need is a glass full of water and several ice cubes.

Put the ice cubes inside the water and wait four-five minutes. After that, if you see condensation forming around the glass, then the air has a good amount of moisture. More vigorous condensation indicates more moisture.

If no condensation is apparent around the glass even after five minutes, then the humidity level is quite low. You should consider getting a humidifier if this is the case.

  • The Thermometer Technique

This process is quite simple as it’ll need two thermometers and some cotton. Despite being simple, the technique is quite accurate. You’ll just need the help of the internet for the results.

Get two thermometers and a cotton ball. Then soak the cotton ball in water and wrap it around one of the thermometer’s bulbs. Make sure the water you use is at room temperature.

Now leave both thermometers at rest side by side for 5-6 minutes. After that, there should be a difference in the acquired values. You’ll find charts on the internet that’ll help you determine the humidity level from that difference value.     

Humidifier or Dehumidifier: Which Is the Best Option for Your Needs

There is no one-line answer to this question. You might need both, and you might need none. It depends on various factors. And to help you decide, I’m putting up a discussion concerning humidifiers vs. dehumidifiers: comparison & benefits.

This comparative discussion below on both appliances should help you find out which one is necessary for your home. I’ll focus on a few decisive factors which should make it easier for you. Let’s dive in.  

  • Humidity Level

Measuring the RH level of your home should give you the nod in the right direction with this choice. The humidity level in your home should stay between 30-50%. Any more or less than that would be problematic.

If the moisture level in your house drops below 30%, getting a humidifier is a priority. The same goes for a dehumidifier if the humidity level gets over 50%. 

  • Conditions and Symptoms

Overly humid air and dry air both cause conditions but of different kinds. Too much moisture causes the growth of various fungi and bacteria. Simple wounds tend to get festering easily, and the spores start getting in your lungs, causing various respiratory conditions to flare up.

If you find traces of these symptoms, it’s high time you got a dehumidifier. It’ll take away the extra moisture from the air, preventing the growth of microbes.

On the other hand, if you’re suffering from skin and eye irritation, cold, and chest congestion, you need a humidifier.

Humidifier’s warm, moisturized air will help you breathe better. You’ll also see your skin and eyes becoming soft and smooth again.  

  • Season and Temperature

Outdoor humidity has a good impact on indoor humidity, and the seasons play a good role in the amount of moisture outside. Summer and Monsoon are typically very humid seasons. During these seasons, a dehumidifier has a high chance of being a necessity to you.

In contrast, Winter is the time of the barren. Typically, the air outside becomes very dry with the drop in temperature. You might very much need a humidifier in your house to fight this dry, arid atmosphere.     

Frequently Asked Questions

  • Can a dehumidifier also be a humidifier?

Not normally. The appliances generally do the exact opposite of one another. So, a humidifier unit can’t simply be used as a dehumidifier or vice versa.

But some units contain technologies installed to handle both functions, a humidifier-dehumidifier combo. If buying and maintaining two different units seem like a hassle, you can just get the combo unit and chill!   

  • Humidifier or dehumidifier, which one is best against COVID?

For a COVID patient, a humidifier will be a relieving option, not a dehumidifier. A dehumidifier might just make things worse.

A humidifier helps a COVID patient by easing the symptoms like difficulty in breathing, cough, sore throat, etc. A warm mist humidifier is a good choice as the warm vapor content will soothe the patient greatly.

People also ask, do humidifiers help with dust? Yes, they do, and it helps patients with respiratory conditions, in general, a lot.


I hope this article helped you learn everything about humidifier versus dehumidifier, knowing their differences.    

It’s important to understand that humidifiers and dehumidifiers can never be an alternative to each other. It’s easier to mix them up and buy the wrong appliance because of their names. So, you must be extra careful while getting a unit for yourself.

Last Updated on February 22, 2023

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Billy J. Weber

Hi. It’s Weber, founder and author of this site Currently you are reading. I am dedicated to provide valuable insights and practical tips to air enthusiasts and anyone interested in improving their indoor air quality.

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