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How to Choose the Right Dehumidifier


In large spaces like warehouses, greenhouses, gyms, schools, hospitals and manufacturing facilities, excess humidity isn’t just uncomfortable – if left uncontrolled, it can destroy a structure with mold, mildew and corrosion. Dehumidifiers are designed to remove moisture and improve air quality by preventing odors, mold and mildew. Commercial dehumidifiers can also help protect equipment from corrosion and damage. Explore the different types of industrial dehumidifiers and the important considerations to help you choose the right size for your facility needs. 

How Do Dehumidifiers Work?

Relative humidity (RH) is the amount of water vapor in the air compared to the total amount the air can hold at that temperature. According to the Environmental Protection Agency, the moisture level in a space should be kept below 60% RH, ideally between 30% and 50%. During the heating season in colder climates, Energy Star notes the RH levels in a building should be between 30% to 40% to help prevent window condensation. If the moisture level is too low, it can cause dry skin and respiratory problems. The dehumidifier that you choose should be able to remove enough moisture from the air to keep the moisture level in the desired range. 

Dehumidifiers remove moisture from the air by using a refrigeration or absorption process:

  • Condensate dehumidifiers, or refrigerant dehumidifiers, use a fan to draw air over a cold coil. Moisture condenses on the coil and is collected in a bucket or drain pan. Industrial condensate dehumidifiers are often used in warehouses or storage facilities, and for water-damage remediation work.  
  • Desiccant dehumidifiers, also known as adsorption dehumidifiers, use a material called a desiccant to absorb moisture from the air. The desiccant is then heated, which causes it to release the moisture. Desiccant dehumidifiers are often used in cold environments where sensitive materials are stored or handled, like museums or pharmaceutical and food manufacturing facilities.   

Dehumidification Method

 Condensate dehumidifiers use refrigerant to remove moisture from the air in two ways:

  • Standard refrigerant dehumidifiers draw air across cooling coils causing moisture to condense and collect inside the dehumidifier. This dehumidification method is commonly used in warm, moist areas. 
  • Low-grain refrigerant (LGR) dehumidifiers pre-cool intake air before sending it across cooling coils to cause moisture to collect inside the dehumidifier. Low-grain refrigerant dehumidifiers are often used for water damage restoration repairs in warm, humid areas since they can collect more moisture than standard refrigerant dehumidifiers. 

Draining Method

Depending on the type of dehumidifier, the collected water can be drained in several ways, including: 

  • Bucket collection: A removable container catches condensed water and must be manually emptied when full.
  • Continuous draining: They continuously drain using gravity to help move the collected water toward a floor drain.
  • Built-in drain pumps: These units turn on when the dehumidifier's reservoir fills with collected water using a drain that sits higher than the dehumidifier.

Types of Dehumidifiers

There is no one-size-fits-all when it comes to selecting an industrial dehumidifier. Every space has unique requirements and challenges; therefore, choosing a system requires careful consideration of several factors, including the facility size, location and climate. 

Dehumidifiers are available in many different styles to meet specific needs, including:  

  • Portable dehumidifiers: They are small and lightweight, making them easy to move from room to room and are commonly used in offices and basements. 
  • Freestanding dehumidifiers: Larger and more powerful than portable dehumidifiers, they are designed to be placed in a permanent location, like a museum, basement or warehouse. Freestanding dehumidifiers are a good option for large spaces or areas with high moisture levels.
  • Wall-mounted dehumidifiers: Used in spaces where continuous moisture removal is needed, like restaurants, pools and fitness facilities, these units are mounted to the wall to help keep floors clear.
  • Ductable dehumidifiers: Also known as whole-house condensate dehumidifiers, they are installed into ducted HVAC systems.

Considering Size and Features

Variables associated with selecting the right dehumidifier size include room size, the building environment, function and much more. Here are some factors to keep in mind to help you find the right dehumidifier for your facility's needs:

  • Humidity level: If the unit doesn’t have a built-in humidistat or display RH levels, use a digital humidity meter or mount a hygrometer near the dehumidifier to help measure the area's RH. A hygrometer can help you to monitor when to turn the dehumidifier on and off. 
  • Size of the space: The size of the space determines the dehumidifier capacity. Calculate the volume of the room in cubic meters to help determine how much air it holds. 
  • Capacity: The daily water removal capacity, also known as the Association of Home Appliance Manufacturers (AHAM) rating, estimates how much moisture the dehumidifier can extract in 24 hours and is typically measured in pints. In 2019, the U.S. Department of Energy released new energy standards for dehumidifiers that changed how dehumidifiers are tested, using cooler, more realistic conditions (60°F compared to 80°F) to more accurately represent a basement setting. Since there is less water to remove in cooler air, dehumidifier capacities have slightly decreased since 2020. 
  • Features: Many dehumidifiers have Bluetooth and Wi-Fi, a built-in fan, timer, auto-restart or remote control. Some industrial units include an hour meter that allows users to track usage for billing purposes. Some dehumidifiers also include a built-in humidistat that allows users to set the desired RH level. Once the space reaches the desired level, the dehumidifier will automatically cycle on and off to maintain the humidity.      


Dehumidifiers require regular maintenance and cleaning to run properly and help prevent mildew growth. Some key steps include:  

  • Wipe down: Clean the machine body with a soft, damp cloth. 
  • Clean filter: Remove the air filter from the unit and lightly vacuum. If the filter is dirty, wash with warm water and a mild cleanser, then dry it thoroughly before replacing.
  • Check manufacturer requirements: Some dehumidifiers, like pump models, require a drain plug to be removed from the bottom of the internal tank to completely drain water before storage.  

By choosing the right type and size of a dehumidifier, you can help to prevent mold and mildew growth, improve air quality and extend the life of your equipment.

Frequently Asked Questions

Q: What’s the difference between office and industrial dehumidifiers?

A: Industrial dehumidifiers are more durable and provide higher water-removal capacity than office dehumidifiers. Industrial dehumidifiers are also specifically designed to manage the humidity levels in a large commercial space and help support construction work or water damage restoration.

Q: How long does it take a dehumidifier to work?

A: Depending on the size of the area, a dehumidifier can take anywhere from a few hours for smaller and medium single rooms to up to 10-12 hours for larger spaces. Most units have a built-in humidistat that can be set to maintain a specific humidity level.

Q: Where is the best place to put a dehumidifier?

A: The best location for your dehumidifier depends on where the excess humidity exists, whether it’s in a living area, basement or crawl space. Use a humidistat or hygrometer to assess the humidity level in the space and find the best location. Many dehumidifiers can safely be placed against walls. However, if you do not have top-mounted discharge, place the dehumidifier away from walls and furniture, so air can freely circulate around the unit. Make sure to keep any drain hoses away from electrical cords or connections.

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The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.