How Does A Dehumidifier Work? (2020 Informational Review)


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There are some things that can make a home smell quite unpleasant and damp air is one of them. Whether you have a dampness problem within your building (penetrating or rising dampness) or your moisture is the result of drying laundry inside or cooking (condensation), it can result in a horrible musty smell with mold growing on your walls and a higher risk of respiratory illness.

So what can you do to avoid this problem? One solution is to invest in a good quality humidifier – an electronic appliance that removes the moisture from the air.

Let’s find out how they work!

Comparison Chart of Our Favorite Dehumidifiers


Our Rating


Danby Energy Star 70-Pint Dehumidifier

Danby Energy Star 70-Pint Dehumidifier

Best Overall

Afloia Portable Electric Dehumidifier

Afloia Portable Electric Dehumidifier for Home 2000ML Water Tank, Home Dehumidifier for Bathroom Dehumidifier for Basement Space Bedroom Kitchen Caravan Office Basement Bedroom Bathroom

Best for the Money

How Do Dehumidifiers Work?

Dehumidifiers remove excess moisture and dampness from the air and create living conditions that are inhospitable to mold, dust mites, and other allergenic organisms. But how do they regulate humidity? What is the mechanism that allows these devices to turn moisture in the air into liquid water?

There are two types of dehumidifiers that remove moisture from the air around us:

  • Refrigerant Dehumidifier
  • Desiccant Dehumidifier

Refrigerant Dehumidifier

The coils inside the refrigerant dehumidifier are colder than the air around them. When the air passes through these coils it becomes colder and its ability to retain and hold moisture falls. Water condenses on the coils and drips into a bucket or pan for disposal.

The now cooled air flows back over the warm dehumidifier motor so that it is slightly reheated before being released back into the room. This warm air going out of the dehumidifier is dry, which is more likely to attract moisture and maximize the dehumidifier’s efficiency.

As the water collection bucket fills up, a plastic float in the machine rises upwards. Once the tray is full, this float activates an electric switch that turns off the fan. An indicator light switches on, telling you it is time to empty the bucket.  

Desiccant Dehumidifier

This electrical appliance uses an absorbent material to extract water from the air. The material is then heated, causing the moisture to drip into the water tank. These dehumidifiers are designed to work better in lower temperatures such as a garage or a conservatory.

However, as compared to refrigerant dehumidifiers, desiccant dehumidifiers tend to use more energy because of the process of warming the absorbent material.

Once you plug in the dehumidifier, it will start to remove moisture that has accumulated in the carpet, wall linings, and furnishings. Therefore, it is important to let it run continuously for the first few weeks. Once the room achieves the desired humidity level, you can use the dehumidifier only when you are in the room in order to maintain this healthy level.

What Are The Components of a Dehumidifier?

Most dehumidifiers have the following components:

Air Filter

The air filter is located behind the grill in the dehumidifier. It traps dust and debris present in the air that could cause contamination of the evaporator fans and condenser coils.

Collection Bucket

This is a container that is located under the evaporator. It collects the condensate water from the evaporator.


This is a pump that compresses the refrigerant gas which runs through the evaporator to start the water extraction and cooling process. This compressed refrigerant gas passes through the condenser where it cools and condenses into a liquid. This liquid refrigerant then moves to the low-pressure evaporator where it evaporates and absorbs the heat from the air moving into the evaporator fins starting the cooling process.


The condenser in a dehumidifier is the heat exchanger that cools down the hot, high-pressure refrigerant gas by changing it into liquid. This liquid then flows through the low-pressure evaporator where it evaporates. During this process, the refrigerant absorbs heat from the air blowing across the evaporator fins. Cooling the refrigerant in the condenser helps increase the efficiency of this heat exchange process in the evaporator.

Condenser coil of a dehumidifier (Source)

Electronic Control Board

The electronic control board in the dehumidifier controls all the major electro-mechanical components. It monitors input from the humidistat and activates the compressor when humidity in a room exceeds the level set by the user. It also shuts off the compressor in case of excessive frost build-up on the evaporator.

Once the fins are clear of the frost and the condensate water drips into the collection basket, the electronic control board restarts the compressor to continue dehumidification if needed.


The evaporator fan helps in cooling and dehumidification by blowing air across the condenser’s heat exchangers and evaporator.


The evaporator cools the air and condenses the water present on its fins to dehumidify the room.


This is a sensor which detects the percentage of humidity or the amount of water vapor in the room. It uses a wire harness connection to provide input to the dehumidifier’s electronic control board.

Review of Our Favorite Dehumidifiers

There is a wide range of dehumidifiers available in the market and finding the one that is best for you can be quiet confusing. We have researched several dehumidifiers to help you make an educated decision and we have found the following to be the best on the market:

Danby Energy Star 70-Pint Dehumidifier


  • Ideal for Spaces up to 4,500 Square Feet
  • Very Easy to Clean and Reinsert the Reusable Air Filter
  • Two-Year Warranty on Parts and Labor Provides Customers With Ease of mind
  • Top Facing Control Panel Makes it Convenient to Set and Customize the Dehumidifier
  • Comfort Mode Automatically Adjusts the Operation to Ensure Your Comfort with Minimal Effort


  • Small Capacity Reservoir Can Hold Only 12.7 Pints of Moisture
  • Lack of Drain Pump Means You Have to Empty the Bucket Often

Our Review

The Danby Dehumidifier is a great appliance that helps eliminate the chance of mold and mildew from flourishing in your home. Whether it is your living room, entertainment space, or basement, this energy-certified unit helps maintain your preferred humidity level for spaces up to 4,500 square feet in size.

One of the quieter models, this Danby model creates as much noise as a refrigerator at 50 decibels. It uses only 515 watts, which makes it one of the most energy efficient dehumidifiers available. This lower usage also creates less impact on the environment, thus making this unit an environment-friendly one.  

The Danby Dehumidifier has an auto defrost function which ensures that the coils do not freeze, nor leave any water in the machine. The electronic digital control panel makes it easy to adjust between the two fan speeds.

It also has a smart dehumidifying function that allows the dehumidifier to automatically control the humidity in a room while taking into account the ambient temperature. The Danby dehumidifier comes with built-in rolling castors, thus making it easier to take this unit from one room to another. In case of a power failure, this dehumidifier will resume operation automatically once power is restored.

Bottom Line

The Danby dehumidifier is a high-functioning and energy-efficient unit which offers a daily dehumidifying capacity of 70 pints for spaces up to 4,500 square feet. It boasts various convenient features such as a 24-hour timer, two adjustable fan speeds, and comfort mode that makes it easier to customize the level of comfort of your living space.

Afloia Portable Electric Dehumidifier for Home 2000ML Water Tank, Home Dehumidifier for Bathroom Dehumidifier for Basement Space Bedroom Kitchen Caravan Office Basement Bedroom Bathroom


  • No Noise Ensures Deep Sleep at Night
  • One-Button Control Makes it Easier to Use
  • Energy Saving Solution to Control Humidity Levels in Your Home
  • Auto Shut-Off and LED Indicator Shows When the Tank is Full of Water
  • Teal and White Color Scheme Gives it a Sleek and Modern Look
  • Small Size Makes it Perfect for Places Like RV, Bathroom, Wardrobe, etc.
  • Portable Design Makes it Convenient to Carry From One Place to Another
  • Two-Year Warranty Shows the Manufacturers’ Confidence in This Product
  • No Compressor Used in its Design Makes it an Environmentally-Friendly Product


  • Some People Find it Expensive Considering its Small Size

Our Review

The Afloia Portable Electric Dehumidifier is a high-performing unit created with safe and innovative whisper-quiet Peltier technology. It quickly absorbs the moisture out of the air in the surrounding area, reduces the humidity in any part of your home, and prevents your clothes and electric appliances from moisture damage, thus providing greater comfort to your life.

This dehumidifier is suitable for removing moisture and dampness from the kitchen, bathroom, RV, office, wardrobe, etc. Moreover, it does not produce any annoying sounds, which allows quiet and sound sleep.

This unit is perfect for small rooms and poorly ventilated places. The automatic shut-off sensor powers down this unit once the reservoir is full, preventing an overflow of the collected water. The front water tank is very easy and safe to remove.

Another great feature of the Afloia is its compact size which takes up very little space and controls condensation perfectly. Its low energy consumption makes it an ideal environmentally-friendly solution for absorbing condensation and dampness.  

Bottom Line

The Afloia Electric Portable Dehumidifier is highly effective at removing excess moisture from the air. If you are looking for a portable and effective dehumidifier for your bedroom or office, then this is the right model for you!


Buying a dehumidifier will help you improve the entire atmosphere of your home. It will get rid of mildew, algae, mold, allergens, and any unpleasant and heavy odors that plague many homes. The above article not only gives you detailed information about the components of a dehumidifier and how it works, but also provides information about two dehumidifiers that we find are the best, based on our testing process.