Your How-To Guide on Cooling a Shipping Container

Shipping containers can get heated up pretty fast, especially during summer when the sun’s heat is at its peak. Unless built for refrigeration purposes, steel shipping containers are excellent heat conductors whose internal temperatures are regulated by their external temperatures.

On a hot day, most shipping containers can heat up beyond 100 degrees. Such extreme temperatures can harm cargo stored or people operating within the container.

Whether you are using it as a storage facility, a primary abode, or an office space, it is important to know how to regulate your shipping container’s temperatures.

As their popularity continues to rise globally, shipping container owners are seeking out innovative and inexpensive ways to keep their container interiors cool. Below are seven tried and proven ways of cooling a shipping container.

Heat-proofing the Container

One simple law of physics is that darker colors absorb more light to generate more heat while lighter colors reflect more light hence minimum heat absorption.

Most shipping containers come in darker shades like red, blue, and green. Due to their heavy light absorption, such colored containers get heated up pretty fast.

Fig 2. Dark-colored shipping containers

Applying lighter colors like white or light gray to your shipping container is a cost-effective way of cooling the container.

Even better, you can use white reflective paint to repel the sun’s rays. If you cannot coat the whole container, focus on the container’s roof as it is the most sunlight exposed part of the container.

Insulate with straw bales

Whether your shipping container serves as a storage facility, home, or office space, it is critical to maintain the right interior temperature. Just like traditional homes insulate to prevent unwanted cold or heat from seeping in, insulating a shipping container’s interior is crucial to maintaining steady temperatures.

Effective insulation prevents external temperatures from affecting internal temperatures. It also serves to ensure that cargo doesn’t become damaged due to excessive heating.

If you’re wondering how to insulate your shipping container, you’re not alone. Many insulation techniques are available in the market, each with its pros and cons. One of the most affordable techniques is straw bales.

Fig 3. Straw bale insulation

Besides being natural and renewable material, straw bales have a reputation for offering some of the highest R-values of all insulating material.

Install a Solar Panel

You can hit two birds with one stone by installing a solar panel on your container’s roof. The solar panel will absorb the heat from the sun hence limiting absorption by the container’s roof. At the same time, the solar panel will be powered by the sun to meet your container’s electrical needs.

Fig 4. Solar panel on shipping container roof

Ventilate

Installing vents at each end of your shipping container is an effective way of naturally controlling your container’s internal temperature, and aids in the long-term prevention of moisture buildup. This process is called cross-ventilation.

There are different types of vents you can choose from: louvered, fixed, and rooftop turbines. Fixed vents are easy to fix and effective in maintaining air circulation. However, they do not alter airflow.

Louvered vents, on the other hand, are more costly but allow flexibility of airflow. Despite their high costs, rooftop turbines are a darling to many container owners because of their ability to provide adequate airflow and prevent moisture build-up.

Ensure your container vents are small in size to keep birds and rodents out.

Install a Window Air Conditioner

You can also use a basic window air conditioning unit to keep your shipping container cool. Your air conditioner’s efficiency largely depends on the size of your container. If you have more space inside your container, an AC unit with a higher BTU will be an ideal choice.

Fig 5. Window air conditioner

Dehumidify

When a shipping container’s interior gets heated up, moisture can sometimes evaporate to the roof of the container.

When this moisture condenses, it drips down to the cargo forming what is often called container rain. This rain can easily ruin cargo by causing water damage, corrosion, and mold.

If your shipping container has electricity, take steps to dehumidify the container using products like thermal liners, absorbent pads, desiccant bags.

Fig 6. Desiccant Dehumidifier

Place your shipping Container in a shade

You can construct an artificial shade for your shipping container away from trees and vegetation. Trees in windy areas can result in the drying out of the container from excess wind. Leaves can also make their way to the top of your container and trap moisture.

A good shade will mitigate direct rays from the sun hence controlling the temperature inside the container.

Arrange Items to Facilitate Airflow

Avoid stacking up items closely or on top of each other. Closely stacked items will prevent airflow in your container. Instead, you can stack your items on shelves or pallets. This way, you will allow air to move freely inside your shipping container.

FAQ’s

How hot does a shipping container get in summer?

Shipping containers can heat up beyond 100 degrees during summer. Containers with darker colors absorb more light and heat up faster than those colored in lighter shades like white. Hot temperatures inside a shipping container can negatively impact cargo.

How do you cool down a storage container?

There are many ways to cool down a storage container. One is by heat-proofing the container by coating it with a lighter paint color like white and light shades of grey.

You can also cool down a container by insulating it with straw bales to prevent unwanted heat from making its way into the container. Air conditioners and dehumidifiers have also proven effective in cooling down storage containers.

How do you make a shipping container not sweat?

Sweating in a shipping container is caused by heating up, which causes moisture to rise, condense then rain back on stored cargo. When ignored, it can cause significant damage to cargo and to the container itself.

To prevent this from happening, you need to dehumidify your shipping containers using products such as thermal liners, absorbent pads, and desiccant bags.

Do shipping container homes stay cool?

Naturally, shipping containers are good conductors of light and heat. Hence, a shipping container home cannot stay cool without several adjustments from owners. To ensure a shipping container home stays cool, you can start by insulating it against unwanted external heat.

You can also ensure your shipping container home is cool by repainting it with lighter colors, dehumidifying it, and installing a window air conditioner.

During the hot weather, a shipping container can heat beyond 100 degrees. Such high temperatures can negatively impact stored cargo or the inhabitants of the container. Since a shipping container is naturally a good conductor of heat, container owners should invest in keeping their shipping containers cool. You can keep your container cool by insulating it against external hot weather, dehumidifying it, installing vents, placing it under a shade, and avoiding closely stacked items to facilitate airflow.

Do not let summer’s heat discourage you from owning a shipping container. By using the techniques discussed above, your shipping container’s interior will remain cool throughout the scorching summer heat.

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  • 3 Responses

    1. Hi, I am looking at purchasing a 40′ new High cube container for on-site storage vs the monthly cost of storage I pay off-site.

      I need to have access for the stored goods so I am thinking about a double door — doors on both ends vs a singe access door on one side.

      I will need AC connected because I live in Central Texas where summers get to 105-110. Also need vents.

      Do you have advice on any of this? I could paint the top of the box with reflective paint. Do you know of any preferred types or brands of AC to use on these boxes? is it very important that I add vents?

      1. Hey Phil,

        Sounds like a solid plan to me. Yes, you’ll want to paint the container a lighter color and use vents, insulation, and AC. Also, you might want to think about cladding the container and use exterior insulation as well, similar to this video. You can check out these posts that should point you in the right direction:

        https://www.containeraddict.com/shipping-container-vents/
        https://www.containeraddict.com/how-to-prevent-condensation-shipping-container-dehumidifer/
        https://www.containeraddict.com/shipping-container-insulation/

        Ryan

    2. I have a 20’ container that I have separated internally to create a wine cellar in the back 8’. The container
      Is buried on the sides and I am considering creating a roof on this back 8 feet with 4X4 posts laid on the sides then covered with galvanized steel roof panels. I would then foam the most forward 4X4 to create a thermal barrier. I am also considering a coating such as Super Therm if that is available in my area.

      Your thoughts would be greatly appreciated!

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