Desiccant Dehumidifiers: How They Work and When to Use Them

By: Evan Scoboria, Last updated: June 26, 2023

In the pursuit of maintaining a comfortable and healthy indoor environment, dehumidifiers play a critical role. They help manage indoor humidity levels by extracting excess moisture from the air, which can prevent mold growth and allergen accumulation. Among the different types of dehumidifiers available, desiccant dehumidifiers stand out due to their unique moisture extraction method and excellent performance in specific conditions. In this article, we'll deeply dive into desiccant dehumidifiers' inner workings, their core components, how they function, and the unique scenarios where they shine. 

Dehumidifier and Plant

Understanding Desiccant Dehumidifiers:

Desiccant dehumidifiers use a moisture-absorbing material known as a desiccant to remove moisture from the air. Unlike refrigerant dehumidifiers, which rely on a refrigeration system to condense moisture, desiccant dehumidifiers attract water vapor onto the surface of the desiccant material, effectively reducing the humidity level in the surrounding air. If you're new to Dehumidifiers and Humidifiers, I recommend reading our article on their differences.

Components and How They Function:

  1. Fan: This component serves as the air's entry point into the dehumidifier, pulling in the air that requires dehumidification. The fan's speed can usually be altered, influencing the rate at which the dehumidifier processes air and its overall efficacy.

  2. Desiccant Wheel or Drum: The desiccant wheel or drum, filled with a desiccant material like silica gel, is the cornerstone of the dehumidifier. The incoming air, guided by the fan, is absorbed by the desiccant material, which actively draws moisture from the air.

  3. Heater: Following absorption, a portion of the dry air undergoes heating and is circulated back over the desiccant material. This regeneration phase discharges the moisture previously absorbed by the desiccant, readying it to soak up more humidity from the incoming air.

  4. Exhaust Fan: The dehumidifier expels the moist, heated air from the regeneration stage using the exhaust fan, generally directing it to a drainage system or outside the building.

This cyclical process, involving air intake, moisture absorption, desiccant regeneration, and moisture expulsion, ensures a consistent reduction in environmental humidity levels while the dehumidifier operates. A clear understanding of these essential components and their roles can enhance your grasp of how a desiccant dehumidifier operates and its suitability for certain environments.

Advantages of Desiccant Dehumidifiers:

Desiccant dehumidifiers possess unique benefits that make them a preferred choice in many circumstances. The first standout feature is their ability to work optimally in cold environments. Since they use desiccants—a material with a high affinity for water—to extract moisture from the air, their performance isn't impacted by colder temperatures. This contrasts with refrigerant dehumidifiers that become less effective in low-temperature settings.

These units are also known for their quiet operation. The sound they produce is significantly reduced because they don't employ compressors—a source of considerable noise in other dehumidifier types. This makes them an ideal choice for spaces where a quiet environment is desired, such as bedrooms, study rooms, or offices.

In terms of portability, desiccant dehumidifiers have a clear edge. They are generally lightweight and compact due to the absence of heavy components like compressors and condensers. This characteristic allows for easy installation and movement, making these units perfect for smaller, space-constrained areas.

Moreover, desiccant dehumidifiers display superior performance even in conditions of low humidity. They continue to draw moisture from the air effectively, unlike their compressor-based counterparts, who struggle as relative humidity falls. This is due to the inherent properties of the desiccant material used, which can attract and absorb moisture even when it's scarce.

Finally, desiccant dehumidifiers circumvent the issue of frost or ice build-up, a common problem in refrigerant dehumidifiers operating in cold environments. Since they don't rely on cooling the air to condense moisture, no cold surfaces are present for frost to form on, making them even more suited for colder climates.

The unique advantages of desiccant dehumidifiers, such as effective low-temperature operation, quieter function, portability, performance in low humidity, and no risk of frost formation, make them an excellent choice across various conditions and settings.

When to Use a Desiccant Dehumidifier:

Desiccant dehumidifiers are best suited for situations where low temperatures, quiet operation, or portability are important factors. Some common scenarios include:

1. Cold climates or unheated spaces: Unlike refrigerant dehumidifiers, which struggle to operate efficiently at low temperatures, desiccant dehumidifiers work well in cold conditions. This makes them ideal for unheated areas like basements, garages, or crawl spaces, especially during the colder months. They are also a good choice for cold climates where the temperature frequently drops below the point at which refrigerant dehumidifiers lose efficiency.

2. Noise-sensitive environments: Since desiccant dehumidifiers operate more quietly than their refrigerant counterparts, they are an excellent choice for environments where noise is a concern. This could include bedrooms, where a quiet environment is essential for sleep, or offices, where noise could be distracting.

3. Areas requiring portability and ease of installation: Desiccant dehumidifiers are generally lighter and more compact than refrigerant dehumidifiers, making them more portable and easier to install. Moving the dehumidifier between rooms or locations or working in a space where a larger dehumidifier won't fit a desiccant dehumidifier could be the perfect solution.

4. Space-constrained applications: Desiccant dehumidifiers' compact size makes them suitable for small spaces where a larger dehumidifier wouldn't be practical. This might include small closets, cabinets, cars, or small bathrooms. Desiccants also work well as a gun-safe dehumidifier, and they are also suitable for enclosed spaces like safes or storage boxes where moisture could damage contents.

5. Low humidity conditions: A desiccant dehumidifier can be more effective if you need to reduce humidity levels in a relatively dry environment. They continue functioning well even at low relative humidity levels, where refrigerant dehumidifiers' efficiency decreases.

While desiccant dehumidifiers are versatile and valuable in many situations, they may consume more energy than refrigerant dehumidifiers and might be less effective in hot, highly humid environments. So, it's essential to consider the specific needs of your space when deciding between a desiccant and a refrigerant dehumidifier.


Desiccant dehumidifiers provide an effective solution for removing moisture in specific environments and situations where traditional refrigerant dehumidifiers may be less efficient. You can choose the best dehumidification solution for your needs by understanding how desiccant dehumidifiers work and their advantages.