What Does a Dehumidifier Do? | Research Shows They Have Benefits

As much as we all love summer, the one thing we can’t stand is high humidity. Not only does it make us feel hotter than it actually is, but it also leads to mold growth, condensation, and musty smells, all of which are bad for our health.

If you are struggling with high humidity (which can also happen during winter), the best gadget for the job is a dehumidifier.

However, before you spend hundreds of dollars on a device, it helps to know what it actually does, and more specifically, if it has any actual benefits.

This article will help you answer the question ‘What Does a Dehumidifier Do?’

What is a Dehumidifier?

Quite simply, a dehumidifier is any device or object that removes excess moisture from the air. Dehumidifiers of some kind have been in existence for centuries.

But with modern technology, we can now track how much moisture is removed, how quickly and, in some cases, automate the process.

While air conditioners also remove moisture from our homes, they are a secondary benefit, so they are not as efficient as dehumidifiers.

Depending on the size of the device, the type, and location, a dehumidifier may remove anywhere from a few ounces of water per day to over 100 pints per day (PPD), even in residential applications.

But, of course, industrial dehumidifiers can do considerably more. *The capacity of a dehumidifier is measured in PPD.

The process of removing water from the air can either cause the room/space to become hotter or cooler, depending on the type of dehumidifier being used.

Types of Dehumidifiers

There are two main types of dehumidifiers. While you may find several variations like homemade dehumidifiers, they tend to fall under these two broad groups:

1. Desiccant dehumidifier

The oldest and most common type of dehumidifier is one that uses desiccant material. This could be a disposable desiccant, rechargeable, consumer-grade, or industrial desiccant.

In every application, the desiccant material absorbs the excess liquid in the air. Disposable dehumidifiers are small packs that are usually placed in closets to prevent the growth of mold.

As they absorb water, the packs become full and should then be thrown away. Unfortunately, these typically only remove a few ounces of water before they become full.

The silica beads you find in new products are technically desiccant dehumidifiers, even though we don’t see them that way. Nevertheless, they are the most common form available.

Rechargeable desiccants also use silica gel beads. These beads absorb water (the water sticks to the surface instead of entering the gels) until they are “full,” usually indicated by the changing color.

At this point, the beads are recharged or reheated to get rid of the moisture they adsorbed so that you can reuse them.

Much like disposable desiccants, rechargeable desiccants also have limited use of a few ounces per day. Most have lower capacities than disposables, but they last much longer and are more valuable as they are rechargeable.

On the other hand, a consumer-grade desiccant has a much larger capacity to remove several PPD.

These devices are electrically powered and use a desiccant wheel and motor to create a constant stream that pulls in air dehumidifies it, and pushes it back into the room.

This method of dehumidification produces warm air. As a result, desiccant dehumidifiers often serve a dual role of also being used to dry laundry during winter.

Due to their design, you can use desiccant dehumidifiers all year round, which is something the other type of dehumidifier can’t do.

2. Refrigerant dehumidifier

When most people think about dehumidifiers today, this is what comes to mind. These units run on a refrigerant (hence the name), similar to what you’ll find in your refrigerator.

A refrigerant dehumidifier, also called a condensate dehumidifier, has a fan that sucks in air unto a cold internal metal plate.

The cold plate causes the air to condense, and the water collected is either drained immediately or stored in a tank. This is a fast process, able to withdraw significantly more PPD than a desiccant dehumidifier.

As powerful as these devices are, they can only function in decent weather. When the temperature drops below 65°F, their capacity can drop dramatically, and most shouldn’t be used when it’s cold.

Desiccant dehumidifiers, on the other hand, don’t lose much performance with changing weather.

The other distinction is that this type of dehumidifier produces cold air instead of warm. As a result, refrigerant dehumidifiers are handy during summer.

Even though they cannot function during winter, condensate dehumidifiers are more popular than desiccant dehumidifiers because they can remove more moisture, are cheaper, and provide extra cooling.

Most people tend to battle with high humidity only during the summer, making winter-capable dehumidifiers redundant.

The most prevalent argument against refrigerant dehumidifiers is that they use, well, refrigerants, which are bad for the ozone layer.

To combat this, manufacturers are constantly working on eco-friendly refrigerants with moderate success.

What Does a Dehumidifier Do? Benefits of a Dehumidifier

Now, we get to the most important aspect. Many products claim to improve air quality and provide other beneficial services, yet many of them are disappointing.

But unlike those, dehumidifiers have a lot of tangible benefits. Here are just a few of them.

1. Reduces the presence of allergens

The most important benefit of a dehumidifier is that it reduces allergy triggers in the air. Mold, dust mites, and dander can cause hay fever-like symptoms and can stir up asthmatic attacks for those with the illness.

As dehumidifiers remove moisture, they also curb the spread of these allergens, making the air safer and healthier. Dust mites need a relative humidity (RH) level of at least 65% to survive.

The United States Environmental Protection Agency (EPA) recommends that the indoor RH level is below 60%, with the ideal level being between 30% and 50%. This level will effectively terminate most dust mites.

2. Curbs or prevents the spread of mold.

Mold spores are constantly all around us. However, they form on walls and closets when they find a wet surface in a humid environment. Besides making your walls or closets look unsightly, mold can also cause health problems.

Molds produce allergens, irritants and may create mycotoxins. They can also damage furniture and clothing. The primary way to protect against mold is to control the moisture level in the air or on surfaces.

Bathrooms, kitchens, and basements are hotbeds for mold growth. While this is usually a result of dampness from leaking taps or pipes, high humidity levels can also be caused.

3. Gets rid of musty smells

When you walk into a humid room, you can smell it. The air is foul and stale, almost like lingering sweat, but much worse. What is even more disturbing is that the musty smell might be a sign that mold and mildew are brewing.

As the dehumidifier absorbs the excess moisture, the smell will disappear. Some dehumidifiers are scented or use charcoal to absorb odors, which is useful when you need to get rid of the stench quicker.

4. Protects your valuables from condensation

If you ever notice your windows or walls being wet for no apparent reason, it means your place is too humid, and your goods are in danger.

Electronics, clothes, curtains, carpets, walls, window panes, and other household products can be ruined by condensation. Luckily, this is easily preventable with a dehumidifier.

5. May help control asthma.

People with asthma often find it difficult to breathe in areas with high RH. That’s because excess moisture makes the air heavier, thus harder to inhale.

A dehumidifier can therefore help people with asthma or other respiratory difficulties to manage their conditions better.

6. Helps with the laundry during winter

Portable desiccant dehumidifiers are very handy at drying laundry, especially during winter when you need to hang clothes indoors.

Unfortunately, even though this causes the indoor humidity level to increase, we don’t have much of an option.

Having a desiccant dehumidifier will help you solve the problem you created and keep your clothes dry, including jackets, scarves, and shoes drenched in snow or rain. 

7. Cools your home during summer

Refrigerant dehumidifiers do the opposite of portable desiccants, making them more valuable when it’s hot. Summer months can be very humid, so getting rid of excess moisture while keeping the air cool and dry is a huge advantage.

Using a refrigerant dehumidifier can also reduce your electricity bill as you won’t need to turn your air conditioner to the highest level to stay cool. However, you would need an energy-efficient dehumidifier to reap this benefit.

8. Controls the growth of other pests

Creepy crawlies like moist and humid environments. Cockroaches and spiders, in particular, can be kept at bay when you use a dehumidifier.

9. Improves air quality

If you live in a home with young children or vulnerable individuals, even those who are healthy, it is important to ensure that the air quality is as good as possible.

By fighting off mold, dander, pollen, dust mites, and foul odors, the air in our home improves significantly.

This is something even people without a respiratory condition can appreciate. While other products can improve air quality, such as air conditioners and air purifiers, they don’t remove excess moisture like dehumidifiers.

What to Look for When Buying a Dehumidifier

The benefit you’ll get from using a dehumidifier will depend on many factors, but the most important one is your own type.

As you can see from the previous sections, dehumidifiers work differently, and some advantages are peculiar to specific designs.

So, to make the most of your dehumidifier, you need to choose the right one. Here are some of the things to consider:

1. Capacity (humidity level)

The first thing that should influence your choice is how much moisture you need to remove from the air.

You can use a hygrometer to measure the humidity level in your house, or you can follow the manufacturer’s suggestions for your climate zone.

Besides the moisture level, you also need to consider the size of the room. Every dehumidifier has a specified space guide, similar to air conditioners.

Once that is established, you would know if all you need is a rechargeable desiccant for your closet or a refrigerant dehumidifier capable of removing 50 PPD or 70 PPD from a large living space.

It is advisable always to get a slightly bigger size than what you require to be on the safe side.

2. Energy efficiency 

According to the EIA, the average American household spends half of their energy bill on heating and cooling. So adding a dehumidifier to the mix will only drive up the cost.

Therefore, it is important to buy a unit that is energy efficient, preferably one with an Energy Star rating.

As mentioned earlier, a dehumidifier can help reduce your cooling cost, but only if the unit is energy efficient. For example, energy Star-certified products use nearly 15% less energy.

3. Noise level

It takes a lot of effort to suck up buckets of water out of the air each day. So, as you can imagine, dehumidifiers can be pretty noisy, especially refrigerant dehumidifiers. It’s like having a second air conditioner.

One thing to look out for when buying a dehumidifier is the decibel (dB) rating. Many manufacturers will claim their products are noiseless, but even then, they may rate their product at 50 dB at the quietest setting.

Bear in mind that the quiet mode or lowest fan setting is when the dehumidifier sucks in the least amount of moisture.

Take your time to read reviews or review buyer guides that mention noise levels when at peak performance.

4. Portability

Being able to move a dehumidifier from one space to another can save you money. In many instances, you also don’t need a dehumidifier to be running in a room you are not occupying at a time.

Of course, for rooms such as basements and crawl spaces, portability is not important, as you would probably need to leave the dehumidifier running automatically.

Alongside portability, you should also consider installation. Portable units with an exhaust hose, for example, may not be useful in all spaces.

Regarding basements, you might also want to consider alternatives such as wall-mounted dehumidifiers.

5. Features

One of the key features you should look for in a dehumidifier is an in-built humidistat with an auto switch-off function.

The dehumidifier might get overworked if you forgot to turn off the switch. When it is left in this state, all the units begin to overheat, and it starts to blow hot air instead.

When the room reaches the desired RH level, these units automatically turn off and return when the RH level increases.

These are particularly useful for crawl spaces and basements. They are also good for living spaces or bedrooms when you are asleep.

So not only will they save you money on electric bills, but they also ensure better air quality – too little humidity can be just as harmful as too much.

Other helpful features include remote control, sleep mode, automatic draining, and reusable filters.

6. Eco-friendliness

When choosing a dehumidifier, it is important to consider its impact on the environment. For example, dehumidifiers that use harmful refrigerants add to climate change.

Disposable dehumidifiers can also be problematic when not made from biodegradable or recyclable materials.

While having a dehumidifier might be necessary, choosing the right one can help lower the damage caused to the environment.


Without question, dehumidifiers are the most effective way to get rid of excess humidity indoors.

Not only that, but they also make the air more breathable for people with allergies and asthma by getting rid of allergens such as mold, dander, and dust mites.

In order to make the most of your dehumidifier, be sure to choose one that suits your climate, room sizes, and environment.

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Melanie Mavery is an aspiring HVAC technician who is fascinated by the trends and opportunities in the HVAC industry. She spends most of her day writing content on home improvement topics and outreaching to prospects.  She's always looking for ways to support HVACs!