Best Dehumidifier for Shipping Container Condensation

Nowadays, shipping containers are not only used for storage and transportation of goods for shipment. They can also become a shed of different kinds or even fitted into a full home referred to simply as a container house. However, no matter its use, shipping containers have a common problem of condensation, which also commonly goes by names like container rain or container sweating. 

This problem is really not that difficult to solve. Whether you’re in the storage business, shipping industry, building your own storage container home, or buying a prefabricated house, there are many simple ways you can ensure that container condensation does not become a nightmare for you. One such way is by investing in the right dehumidifier for the space. You must also improve the container’s insulation and ventilation while considering the location’s temperatures and humidity levels. But first, we’ll talk about how condensation forms and why you need to prevent it in a shipping container.

What is Shipping Container Condensation?

Shipping Container

A few definitions are in order before we proceed. Relative humidity refers to the amount of water vapor present in the air compared to the maximum amount it can hold at a given temperature. The dew point is the temperature at which the air cannot hold any more moisture, reaching a relative humidity of 100 percent. 

Now, condensation occurs in a shipping container (or really any other place) when the walls 

Become colder than the air’s dew point inside the container. A standard shipping container is basically a hollow metal structure and thus conducts heat extremely well, absorbing heat from warm bodies and transferring it to cold objects. So when the weather abruptly changes outside, the temperatures inside the container fluctuate along with it.

As the cold metal walls cool down the air inside, the air reaches its dew point where it can no longer hold the moisture. This forms water droplets or condensation on the container walls and roof interior. Notice how when you put cold water in a glass, the condensate appears on the outer side of the glass. Meanwhile, if you put hot water, the condensate appears on the inner side of the glass.

Condensation can ruin the container’s interior and drip onto the items in storage. This can damage the goods in cargo or your personal belongings through rusting, corrosion, and mold growth.

What Causes Condensation in a Shipping Container?

Before you learn how to reduce condensation in shipping containers, it’s important to understand the factors that contribute to its formation. The amount of condensation that forms inside a shipping container depends on temperature, ventilation, the type of goods in storage, the remaining open space, and container usage.

The temperature largely depends on the location and the climate in the area the shipping container traverses. As it travels through its transportation route, it can face sudden changes in temperatures. As temperatures change, moisture can build up in the air, causing condensation.

Proper ventilation promotes airflow inside a shipping container. Airflow helps equalize the air temperature inside with the temperature outside, preventing moisture buildup. Depending on the type of items in the container, you may need to add ventilation to the space.

That said, some types of materials are more likely to add moisture to their surrounding air. Organic materials including paper, wood, and food items have high moisture content. As temperatures change significantly, these items may release some of the moisture into the air, causing it to accumulate on the container walls. Without properly sealed or waterproofed packaging, these items can also lead to excess moisture.

Furthermore, when the container is not packed to its full capacity, there is more space for the air and the moisture to build up. Thus, the bigger the open space, the more likely condensation forms.

Lastly, how you use the shipping container can affect how much condensation forms inside. The frequency at which the doors are opened and goods are loaded or unloaded into the container can drastically change the temperatures and moisture levels inside. Again, depending on the type of items inside and the weather conditions outside, frequent exchange of the indoor and outdoor air may further cause moisture buildup.

Effects of Condensation in a Shipping Container

Container rain or a buildup of moisture can cause water damage to stored goods and the container itself. Depending on the types of items in your storage and transit, condensation can be extremely damaging. Also, the longer they are in storage, the more chances for moisture to cause damage.

Whether you use the container for business, recreation, or residence, container condensation can incur greater loss and higher repair costs if not controlled as soon as possible.

Firstly, moisture can cause damage to metal surfaces including the container walls and ceiling. Rusting of metal is not only unpleasant to look at but it also weakens the structure over time.

Excess moisture on wooden items can lead to mold or fungal growth as these fungi feed on organic materials like wood on any moist surface. Condensation can also cause wood to rot, swell, or warp. 

Moisture damages interior coating as well. You may notice flaking of paint or varnish on walls or damage to flooring and roofing adhesives and permeable insulation. In severe cases, it’s also possible to find visible water stains and even standing water as the condensation drips down onto the floor.

Condensation can also cause damage to equipment and electronics in storage through corrosion in the coils and wiring.

Lastly, moisture and mold growth can cause musty odors and a lack of comfort as well as health issues including symptoms of allergy and other respiratory conditions. To prevent condensation helps avoid these problems in a shipping container.

How to Stop Condensation in a Shipping Container

Moisture control is standard maintenance in any shipping container, whether it’s in storage or transit, or parked in a backyard. Keeping the inside dry is the simplest way to prevent moisture accumulation. However, this isn’t always easy, depending on the container’s purpose and location. Below, we provide four common solutions to excess shipping container condensation.

Condensation in a Shipping Container

Insulation 

Improving the insulation in a shipping container can greatly reduce the moisture levels present in the air. Container insulation provides resistance to heat so that warm air remains inside while the cold air is out. This keeps the inside of your container warmer than the air’s dew point, In turn, this prevents sudden changes in the ambient temperature that can lead to condensation. The proper materials for insulation largely depend on the climate. 

Ventilation

Adequate ventilation equalizes the indoor and outdoor temperatures, therefore reducing condensation due to the temperature difference. Ventilation releases warm, moist air out of the container, and cool, dry air from the outside is pulled in, thus reducing moisture. However, adding ventilation to your container may not always work in your favor. If it’s extremely humid outside, then ventilation can only add more moist air into the interior of the container.

Desiccants

Desiccants are made of hygroscopic substances that readily take up moisture from the surrounding air. There are many commercially available desiccant products that are made to absorb or adsorb excess water from the air in a given space. This reduces the dew point inside the container, preventing condensation. 

Shipping containers often include desiccants inside to help reduce moisture from products and packaging. In fact, a lot of products packed in bottles or boxes like vitamins, dried foods, and even shoes and bags come with little packets of desiccant to prevent moisture. Shipping and storing boxes upon boxes of these products require more desiccants to keep moisture levels down.

Desiccants come in a variety of forms. Depending on the purpose of your container, you can choose from the different types of desiccant. There are those that come in bags you can hang from the ceiling or around the container walls to prevent dripping moisture onto the goods. Shipping companies may also use blankets or pads of desiccants in a leak-proof design placed underneath or above the packaged items to protect them from moisture. 

Dehumidifier

If desiccants are not enough to control condensation inside the container, consider electric or non-electric dehumidifiers. Technically, desiccants are a type of non-electric dehumidifiers also called moisture absorbers.

If you need more power to reduce moisture inside and the container has access to a power supply, then a dehumidifier is the most effective way to sucj moosture out of the space. However, besides providing a strong power source, you need to perform regular maintenance such as emptying the tank of the collected moisture and cleaning the unit. Below we have a small selection of dehumidifiers you can use in a shipping container 

Best Dehumidifiers for Shipping Container

IMAGEPRODUCT
  • Dimensions: 6.06 x 9.25 x 5 inches
  • Weight: 3.43 pounds
  • Coverage Area:
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  • Dimensions: 9 x 8.25 x 2.88 inche
  • Weight: 1.2 Pounds
  • Coverage Area: 333 Cubic Feet
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  • Dimensions: 6 x 6 x 8.5 inches
  • Weight: 2.4 Pounds
  • Coverage Area: 150 Square Feet
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  • Dimensions: 15.5 x 11.34 x 19.78 inches
  • Weight: 36.32 Pounds
  • Coverage Area: 22 Pints
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Dehumidifiers come in different types and sizes. If you want to simply absorb moisture before it gets worse, then DampRid is a common choice for many. It’s available in a wide range of container sizes suitable for different purposes.

DampRid Hanging Bag, Moisture Absorber

Eva-Dry E-333 Wireless Dehumidifier

Eva-dry E-333 Renewable dehumidifier

A popular mini dehumidifier also using desiccant technology is the Eva-Dry E-333. Unlike common desiccants or moisture absorbers that must be disposed of after use, this renewable dehumidifier can be recharged every few weeks then it’s again as good as new.

Pro Breeze Mini Dehumidifier

Pro Breeze Dehumidifiers for Home, 225 sq ft Mini Dehumidifier

For storage containers with a power source or even a small container home, the Pro Breeze Mini Electric Dehumidifier should be good enough to provide moisture control. It uses Peltier technology for a low-consumption and whisper-quiet dehumidification of small spaces.

Frigidaire 22-Pint Dehumidifier

Frigidaire 22-Pint Dehumidifier

For a full-sized container home in humid climates, you may also need a full-sized compressor dehumidifier such as the Frigidaire 22-pint. The brand is known for quality appliances and this is evident from the unit’s sleek design and structure to its advanced controls. If you don’t want to empty the water collection tank manually, you may also attach a hose to the outlet for continuous drainage via gravity.

Conclusion

Whichever you choose, it’s important to know the exact needs of the shipping container depending on its purpose, where it is stored, or where it is traveling through. Sudden changes in the environment can cause excess moisture and the container must be equipped to handle humidity and its potentially damaging effects.

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