How To Install a Commercial Dehumidifier

Where and how you set up a commercial dehumidifier can make all the difference in how effective it is in controlling the humidity and indoor air quality. Portable units are usually simple enough to operate on your own, but most whole-home dehumidifiers usually require professional installation. 

That said, it’s good to understand the installation steps that a professional installer will need to go through so you can better discuss and appreciate any installation quotes you get. Or, if you are truly feel adventurous and are very handy with DIY projects, you could try tackling installation yourself (if allowed in your area).

A dehumidifier’s main purpose is to extract moisture in the air, helping you maintain comfortable levels of humidity. Dehumidifiers come in a wide range of sizes and with different features for every need. If you decide you need one for your home or business, we’ll guide you through the process of how to install a commercial dehumidifier with five key steps.

1. Choose the right type and size of dehumidifier.

First, you need to find the best commercial dehumidifier that meets your particular needs. If you have humidity issues in only one specific area, a standalone unit might be enough. But if you need to dehumidify multiple areas on different floor levels, it’s probably best to find a large model to add to your central HVAC (heating, ventilation, air conditioning) system. 

A centralized dehumidifier can be connected to your existing HVAC ductwork to control the humidity throughout the whole property. It will work together with your installed heater and air conditioners. For your convenience, you can monitor operation with a remote humidistat. This offers a hassle-free solution to excess humidity and moisture issues year round, as well as an improved indoor air quality and lower energy bills.

If you’re specifically looking for a low-temperature application, you’ll want to check out our guide on commercial desiccant dehumidifiers.

How much does it cost to install a commercial dehumidifier?

Whole-home commercial dehumidifiers can cover anywhere from 1,000 to 8,000 square feet or more. Costs start at around $1,000 and go up to $3,000 or more, depending on the brand. Professional commercial dehumidifier installation will typically add at least $500 to your expenses, plus other materials you will need. Obviously, a portable commercial dehumidifier costs a lot less but covers smaller areas, around $600 to $1,500 for 1,000 to 6,000 square feet.

Aprilaire 1820 Crawl Space Dehumidifier
Aprilaire 1850 Whole-home Dehumidifier

Once you have determined which type of dehumidifier you need, it’s only a matter of finding the right size. You must consider the area of your space, the relative humidity, and the ambient temperature, among other factors. 

Check out our full guidelines on sizing your commercial dehumidifier here. It’s crucial to sort this out before anything else, or your dehumidifier will only waste energy.

2. Pick the best location for your commercial dehumidifier.

Standalone commercial dehumidifiers can be used in most any place with moisture issues. Besides their portability, the easy installation process is another advantage of using this type of dehumidifier. Just find an ideal location, plug in and turn it on.

Make sure the commercial dehumidifier you get has adequate capacity to dehumidify the whole area. To optimize performance, track down the main source of high humidity so you can isolate it. This way it will be easier to remove the moisture in one specific area. 

Wherever you choose to place the dehumidifier, it is important to maintain airflow. This means you don’t want to place the unit in a corner or too close to furniture. Clear the area from any obstacle and ensure that the air can flow freely from the inlet to the outlet valves. 

One ideal placement would be in the middle of the room for maximum coverage. Although, having a big and loud appliance in the midst of your living or working space is a hassle, so most people find it more convenient to place the dehumidifier in one corner or side of the room. Alternatively, you can look for a wall-mounted or overhead dehumidifier to save floor space. If there really isn’t any good location inside the room, you can set up the unit outside and use ducting.

You may also want to keep your dehumidifier easily accessible for regular cleaning and maintenance. You can work around it in either case, but ideally, you want the unit as close to a power supply as it can get. Drainage is another thing to consider when picking a location, but more on that later.

Quest Dual 155 Overhead Dehumidifier

How to add a dehumidifier to your HVAC system

If you do go with a whole house dehumidifier, it can be ducted to your HVAC system to dehumidify the air as it enters the space. The best way to install this type of dehumidifier is by adding a dedicated return duct that carries the air into the unit. It is also possible to connect the unit to an existing return duct. To send the processed dry air back to the main air stream, you need to connect the unit to your HVAC supply plenum.

Dri-Eaz Revolution with Duct Attachment
Dri-Eaz Revolution with Duct Attachment

3. Select a drainage method.

Commercial dehumidifiers extract excess moisture from the air and turn it into condensate. This water is then collected in an internal tank which slides out for manual drainage. Most commercial dehumidifiers feature continuous draining via gravity. This can be really handy if you don’t want to have to check on the unit all the time, especially if it’s in an inconvenient location like a crawl space or basement. 

One possible downside is that you need to place it near a sink or drain. Gravity drainage will only work if the unit is elevated high enough from the drain so that the water can drip down through the hose.

Santa Fe Compact70 70 Pint Dehumidifier for Basements
Santa Fe Compact70

High capacity units also offer an internal pump which automatically drains the condensate. This may be a necessary feature for rooms without a floor drain or sink available. With an automatic pump you can have the drain hose run up a sink or through a window to release the water. Each model has an indicated height limit in which you can position the hose. For a centralized unit, you may need to connect a PVC pipe to your existing drainage system. It’s highly recommended that you get a professional for this task.

4. Set your preferred humidity level.

Once your dehumidifier is all set up, you need to put in your target humidity level. You can do this either through the onboard controls or a remote humidistat. The ideal range for the average person is between 35% and 45%. Anything below 30% is considered too dry, and above 50% is too moist. For storage areas and other commercial spaces, you may adjust the level accordingly. If you have specific needs, make sure your dehumidifier has the ability to perform as required while maximizing your energy savings.

Even with a humidistat which automatically adjusts the indoor humidity, it’s a good idea to monitor humidity levels just to be certain that your unit is working effectively. If you want you can also set up a separate hygrometer to keep track of the amount of humidity.

5. Observe proper maintenance.

For any appliance, frequent cleaning helps maintain its proper functioning. Your dehumidifier is no exception. While it extracts moisture from the air, it also collects dust, mold, and bacteria. If left for long, it circulates unhealthy and unpleasant smelling air within your entire space. To ensure your health and comfort and help your dehumidifier last long, clean the unit at least every few weeks.

Before you proceed to cleaning or disassembling any parts, make sure the unit is shut off and unplugged. Disconnect it from ducting or pipelines. Once it’s safe, you can start by wiping the exterior. Be extra careful not to spray water or any cleaning solvents directly on the unit. Take out the air filter and wash it as recommended by the manufacturer. You can do this with a sponge and liquid soap. You can also replace filters as needed. If it’s particularly cold in your area, you may need to check the condensing coils for frost buildup. Vacuum the insides to remove any remaining dust or debris. Let everything dry completely before reinstalling. 

These are only some basic rules you can follow to keep your dehumidifier working effectively and efficiently. Each model has specific guidelines for usage, troubleshooting, and maintenance. Consult the user manual for more detailed instructions.

Benefits of Using a Dehumidifier

Saves your air conditioner

A dehumidifier is an invaluable addition to your HVAC system. During hot and humid summer days, your air conditioning unit may not be enough to keep the indoor environment comfortable. 

An air conditioner lowers the temperature, and in turn, helps reduce the humidity. However, cooling down heavily moist ambient air makes the job a lot tougher for your air conditioner, which will equate to high air conditioning bills. All the while, air conditioners alone will not be able to remove all the excess moisture from the air.

Meanwhile, in cold and wet climates, you may not even need to run your air conditioning unit. Yet, the cool air remains heavy with moisture. Of course you can still turn on the air conditioner to try to keep the humidity in check, but this is neither effective nor economical. 

Reduces allergies

Excess humidity inhibits mold and mildew growth. Touching mold or inhaling mold spores may cause allergic reactions such as sneezing, runny nose, eye and skin irritations. It can also lead to allergy-induced asthma attacks and other respiratory conditions.

Dust mites are among the most common allergy and asthma triggers at home. They thrive in humid conditions and trigger allergy symptoms similar to hay fever. They cannot survive when relative humidity drops to 50 percent.

Improves indoor air quality

High humidity levels also decrease indoor comfort. Humid air can’t absorb your sweat since it is already saturated with moisture. The more humid the air the more it becomes difficult to breathe. Using a commercial dehumidifier for the whole house keeps out excess moisture and odors, greatly improving indoor air quality for your health and comfort.


You may not have considered it before, but dehumidifiers can perfectly complement your HVAC system. It can help lighten the load on your AC and reduce energy bills. Only a dehumidifier can effectively control high humidity levels.

Whether you go with a portable or central unit, the first thing you need to do is find the most compatible dehumidifier for your space. Consider the size of the area, its present condition, the temperature and moisture content, and other features you may need.

A large portion of the installation process is just finding the best location to operate your dehumidifier. Enlist the help of an expert when working with ducts and pipes to connect the unit to the rest of your HVAC system. If you have particular concerns, read through the manual or contact the manufacturer for assistance.

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