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How Does A Dehumidifier Work?

Most houses have dehumidifiers in many areas, especially in coastal regions. Even a relaxing day can be ruined if the humidity level is high. Humidity refers to the vapor or water molecule concentration in the air for a certain day. Higher humidity can cause a lot of problems for anyone.

So, live in an area where the moisture content in the air is always high. A humidifier can make your home more comfortable. It is a simple machine that removes the water vapor from the air inside your home and keeps the humidity level at the ideal range. Not just that, if anyone has asthma or an allergy, they can also get some relief with the help of a dehumidifier.

Anyone who has purchased or is planning to purchase the dehumidifier machine may have wondered about how the machine works. Well, let’s check out its working mechanism in detail.

What Is A Dehumidifier?

A dehumidifier is a machine that removes the excess water vapor from the air and keeps the humidity comfortable.

Usually, three types of dehumidifiers are seen in the market. Each of these uses different methods to cut down the moisture content in the air. Here are the parts of different dehumidifiers according to their type:

1. Refrigerant Dehumidifiers/ Room Humidifiers

These are the most common dehumidifiers that use the same cooling process as a refrigerator for an air condenser. These are ideal for maintaining indoor humidity.

But, refrigerant dehumidifiers are not ideal for cooler temperatures as the metal cooling coils or plates become less effective as the temperature falls below 18 degrees C. But, many models come with advanced mechanisms to handle lower temperatures and can work even at lower temperatures.

Even though the design can vary, most dehumidifiers have three parts:

  • Compressor cooling coils : The cooling coils are mostly made of conductive materials like copper
  • Fan compressor : It compresses and expands the cooling gas and cools the coils present in the compressor.
  • Reservoir : The reservoir collects and captures the emitted heat while the cooling process and dehumidification continue.
  • Reservoir- :Plastic bucket or a hose that drains the collected water

Depending on the model design, a dehumidifier can also come with this component-

  • Humidistat : It allows you to maintain a fixed humidity level in your home. The humidistat is usually made with a relay amplifier and a sensing element. The sensing element comes with two alternate metal conductors. When the humidity changes, the conductors develop electrical resistance. The relay amplifier then measures the resistance, and it, in turn, gives a signal to turn off or on the dehumidifier.

2. Desiccant Humidifier

The Desiccant humidifiers use a desiccant or water-absorbing material to decrease dehumidifiers. Usually, most desiccant humidifiers use highly absorbent silica gel.

The best part about this type of dehumidifier is that it can work even in cooler areas and lower temperatures, as the silica gels do not lose their absorbing capacity with the temperature drop. Furthermore, the desiccant humidifiers are also smaller and lighter in size. But, these dehumidifiers require a lot of power, nearly 600-8000 watts per hour.

The parts:

  • A desiccant wheel : a large rotating wheel with a silica gel surface
  • Drive motor : The drive motor that rotates the wheel
  • Blower : It blows hot air on the wheel

3. Whole House Ventilation Humidifiers

The whole house ventilation system is ideal if you want a complete solution for your home. A single machine can remove the humidity from the air, and you do not need to invest in different machines for each part of your house.

Usually, the machines are grill mounted in the hallway. The air coming from the ventilation network is passed through the machine. It is dehumidified, making the air around your home fresh and crispy. A whole house dehumidifier can remove nearly 10 gallons or more water in a day.

It can be your ideal choice if your area has extremely humid and hot weather, and portable or individual dehumidifiers are not enough to maintain a comfortable humidity level indoors.

The whole house dehumidifiers are similar to an AC unit. It contains a condensing coil, an indoor ac unit, and the AC ducts that connect the machines. But, its main purpose is to collect the excessive humidity from the air instead of regular temperature control.

Why Do You Need Dehumidifiers?

You need a dehumidifier machine if the air in your area is hot and extremely humid; the machine can cut down excessive heat and give you a comfortable environment inside your home. It artificially maintains the humidity level to the normal range when the weather outside is not ideal.

How Do Dehumidifiers Work?

As you already know, each type of dehumidifier works differently and uses different dehumidification methods. Here are the details-

1. Refrigerant Dehumidifiers

The fan draws the air inside the machine and through the cooling coils. In the meantime, the compressor fan compresses and expands the refrigerant gas to cool the coils down.

The drawn air then passes through the cooling coil and condenses and cools. The coil then pulls out the moisture from the air and collects it. This extracted water is discarded outside through the reservoir. If your dehumidifier has a reservoir bucket, you may need to empty it occasionally. Some models also come with a reservoir hose connected to the pipeline or outside to let the water out.

The machine then reheats the air, and the dehumidified air enters the room.

2. Desiccant Dehumidifiers

Ambient air is first drawn inside the dehumidifier and is passed slowly through the silica gel wheel. The gel then collects the moisture from the air.

The dry air is then expelled into the room. In the meantime, a small portion of the dry air is reheated. It is called regeneration air. It is then blown on the silica gel surface with the help of the blower. This warm air then recollects the water from the silica gel surface and reactivates the gel molecules. This air is expelled back into the environment.

The condensed water is drained in a reservoir bucket or hose.

3. Whole House Ventilation Dehumidifiers

The whole house humidifiers use the HVAC system to keep the air fresh and crisp. The ambient air enters the humidifier through the HVAC system.

The machine then uses its evaporator coil to cool the air and condense the water vapor. The collected water droplets are then collected in the reservoir and expelled.

The dehumidified air then passes through the AC unit and is cooled down to the desired level. It is then released inside the home.

Benefits of Dehumidifiers

1. It keeps the info per environment comfortable : Higher humidity prevents the human body from cooling off by emitting the water as sweat. It, in turn, leads to lethargy and hyperthermia. Dehumidifiers remove the excessive water content from the air, making it more breathable and comfortable. It also helps us cool off naturally instead of always feeling sweaty and lethargic.

2. Provides better air quality :Due to pollution and other issues, the air in most cities is highly polluted and extremely humid. The dehumidifiers remove the pollutants and the humidity and improve the air quality drastically. Hence, you get healthier and better air and environment inside your home.

3. It can help to remove allergens like molds and, dust mites, Pollens from indoors :Patients who suffer from asthma, allergies, or COPD can get some relief from dehumidifiers. Since these machines remove the excess water from the air, they can also remove allergens like mold, dust motes, pollen, and animal dander from the air.

Molds are the most common factor that damages your health, home, and even furniture. Since the humidity is reduced, the chance of mold growth also decreases, and you get a fresh home without any mold infestation.

Similarly, dust mites also grow in humid weather. With dehumidifiers, you know your home is fresh and less humid. It, in turn, decreases the chances of dust mite infestation.

A dehumidifier also filters the air and removes pollen and pet dander carried by water molecules present in the air.

In simple words, a dehumidifier can remove most of the allergens from your home indoors, keeping the environment safer and free of allergens. Hence, you get relief from allergic bouts and a healthy indoor environment.

4. It gives relief from asthma : Excessive humidity makes the air heavier, and breathing may become difficult for those with asthma. The dehumidifiers remove the excess moisture from the air, making it lighter and easier to breathe.

If you are suffering from mugginess and breathlessness during the summer, installing a dehumidifier can greatly help you. Furthermore, a 2013 study also indicated that dehumidifiers can help relieve symptoms of chronic asthma.

5. It can help those who have chronic COPD : COPD or chronic Obstructive Pulmonary Disease and difficulty breathing due to long problems can get some help with dehumidifiers.

Factors To Consider Before Buying Dehumidifiers

1. Water Removed Per Day : The better the water removal indicates better dehumidification capacity. A regular dehumidifier can remove 10-100 pints of water per day. Getting a dehumidifier that can remove 40-70 pints of water daily is better. The machine will be enough for most climates throughout the year.

2. Efficiency :You need to invest in a machine that is efficient and saves energy. After all, the dehumidifier may work for 24 hours regularly. Hence, you need to check out the energy the machine consumes per liter of water removed from the air. Most dehumidifiers come with a rating of efficiency in the unit L/KWh.

3. Wattage : Dehumidifiers with higher wattage can work better but consume a lot of energy. So, check out the wattage rating before you shop.

4. Climate : You need to choose the dehumidifier based on the climate and weather where you live. If you live in very hot and humid weather where the air always seems damp and musty, you will need a humidifier with a capacity of 40-780 pints per day. If the climate is mostly rainy and you get visible condensation in the windows, go for a dehumidifier that can remove 50-70 pints of water per day.

5. Room Size : The room size also works as a deciding factor while shopping for a dehumidifier. If you have a 500-1000 sq ft room, a machine with a capacity of 40-50 pints per day is enough. But, if you have a bigger sized room, say 1500-2000 sq ft, a dehumidifier of capacity 50-70 pints per day is ideal.

Dehumidifier FAQs

1. What is the ideal humidity level for my home?

Ans: The ideal humidity level inside your home should be around 30-50%.

2. How long will it take to get the moisture under control?

Ans: A dehumidifier can remove the moisture within one hour. You can start to feel the difference just after thirty minutes.

3. How do I know how big a dehumidifier I need?

Ans: The dehumidifier size depends on the climate and the room size. Usually, a dehumidifier of water removing capacity of 40-70 pints per day is enough for a 500-200 sq ft room.


Dehumidifiers are machines that can remove excess moisture from the air. In case the air outside is extremely humid and uncomfortable. There are different types and sizes of dehumidifiers available in the market. You can choose the desired model depending on the local climate, room size, and preference.

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