A 20ft reefer container is a unit that helps keep your temperature-sensitive goods safe during transport by using advanced cooling technology to protect the cargo and retain its qualities.
The following information covers the dimensions, technical performance, and loading limits to help you plan for your next shipments.
External Dimension
A 20ft reefer container has external dimensions of 20ft (6.06m) in length, 8ft (2.44m) in width, and 8.6ft (2.62m) in height.
Internal Specification
The 20ft reefer container has a total volume of 28 cubic meters. The table below shows its specifications.
| 20 ft Reefer Container Specification | ||
| Specification | External | Internal |
| Length | 20ft (6.06m) | 17.8ft (5.45m) |
| Width | 8ft (2.44m) | 7.5 ft (2.29m) |
| Height | 8.6ft (2.62) | 7.4ft (2.25m |
| Door Opening and Payload | ||
| Door Width | 7.5 ft (2.29m | |
| Door Height | 7.3ft (2.24m) | |
| Max. Payload | 27.49 t | |
| Internal Capacity | 28 m³ | |
Interior Dimensions
The interior space of the reefer measures 5.45 meters in length, 2.29 meters in width, and 2.25 meters in height. The door opening is 2.29 meters wide and 2.24 meters high to allow for smooth loading.
Insulation Materials
These units maintain the ideal temperature using polyurethane that is 60-100mm thick. Some containers also feature vacuum insulation panels (VIPs) that are between 20 and 30mm thick.
Floor Design
The floor uses a T-bar aluminum design to help air flow under the cargo. This build also allows for a maximum payload of 27.49 tons.
Technical Performance
Temperature Range
The 20ft reefer container keeps a precise climate to protect your cargo. Most units are designed to hold temperatures between -30 °C and +30°C for various goods. This range allows the container to handle everything from frozen to fresh produce and pharmaceuticals.
Cooling Speed
The 20ft reefer container uses a high-capacity refrigeration system to reach the ideal temperature and maintain its state. This process is known as pull-down time, which measures how quickly the unit can bring the internal air to the desired set point.
The speed is determined by the ambient temperature outside and the initial temperature of the cargo being loaded. Because these units are designed for temperature maintenance rather than flash freezing, the cooling speed is most effective when cargo is already pre-chilled.
The system works by continuously circulating air to remove the heat, which helps the internal environment quickly reach its target temperature.
Airflow Management
The refrigeration unit maintains consistent interior conditions by pushing cold air through a T-bar aluminum floor. This floor design acts as a pressurized chamber that forces air to move vertically up and through the cargo. This constant movement prevents heat pockets from forming while keeping every part of the load at the required temperature.
To maximize this circulation, cargo must be stacked correctly to avoid blocking the air paths. For example, pallets should not exceed height limits, and the floor must remain clear of obstacles that could obstruct the flow.
Proper loading allows the air to reach the back of the container before returning to the unit, which creates an equal thermal environment throughout the entire space.
Power Systems
A 20ft reefer container relies on a dual power approach to maintain its internal climate using external electrical sources when stationary and portable fuel-based systems during transit.
Cooling Equipment
The primary power system consists of an electric refrigeration unit that connects to a 440/460V three-phase power source. This system drives the compressor and fans required to circulate air through the T-bar floor.
Generator Use
When the container is away from a shore-side power source, such as on a truck or in a staging area, it uses a Generator Set or Genset. This portable diesel generator provides the necessary electricity to keep the cooling unit running while the container moves between locations. This keeps the cargo protected even when disconnected from the main power source.
Operating Hours
The total time a 20ft reefer unit can run depends on the Genset fuel tank capacity and how well the cooling cycle works. Most diesel generators have enough fuel to run for 72 to 120 hours before they need a refill. This time allows for long trips.
When plugged into an electrical grid, the unit can run 24 hours a day. It will keep running as long as there is a steady power supply. To make sure the unit runs for a long time without breaking, proper maintenance should be done regularly.
Loading Capacity
Pallet Capacity
A 20ft reefer container is designed to hold cargo based on the pallet type used. It can fit 9 GMA pallets or 11 Euro pallets in a single layer. This difference in count is due to the varying dimensions of each pallet style.
Weight Limits
The maximum cargo weight for this container size is 27.49 tons. Staying within this limit is important for safe transport and handling. Proper weight distribution across the floor helps the cooling system work correctly.
Final Thoughts
A 20ft reefer container is a reliable solution for transporting temperature-sensitive goods. Its performance relies on a steady power supply and efficient airflow through the T-bar flooring.
Whether you are using a Genset or an electric grid, regular maintenance is a must to avoid system failure. Following the given pallet and weight limits ensures that the cargo stays safe and the cooling system works as intended.
If you have any further questions or need a 20ft reefer container that meets your needs, our team of professionals is always here to assist you.
You might also find this blog post useful
Different Types of Reefer Containers
Reefer Container Guide: Common Problems and Easy Repairs
A Guide to Reefer Container Temperature Monitoring and The Challenges You May Encounter
About The Author
Evan Wang
I am Evan Wang, the General Manager, Marketing Director, and SEO Expert at Sunnyda Cold Room. I have over 20 years of experience in the refrigeration industry, and my expertise is in commercial refrigeration solutions.
I’d be delighted to share practical ideas about refrigeration products, project selection, export trade, SEO, and marketing.
Let’s connect!
