A reefer is a refrigerated shipping container with its own refrigeration unit, powered by the ship, the terminal or a generator on the road. Here are the sizes, the temperature range, the loading rules that prevent most cold-chain claims, and how reefers move inland.
A reefer container is an insulated shipping container with a built-in refrigeration unit that holds a set temperature, usually anywhere from about -30 °C to +30 °C, as long as it has power from the ship, the terminal or a diesel genset on the road. The 40ft high cube reefer holds about 67 cubic metres and the 20ft about 28. It keeps cargo at temperature rather than cooling it down, so goods are pre-cooled before loading, stowed below the load line and kept clear of the floor so air can reach the whole load.
Written by Aleksandrs Smetanins, President, Qeep Logistics · Last reviewed November 3, 2026
A reefer container is a refrigerated shipping container. It has the same outside dimensions and corner castings as a standard container, so it stacks on a ship and rides a chassis like any other box, but the walls, floor and doors are insulated and one end holds an electric refrigeration unit.
That unit does not make its own power. On a ship it plugs into the vessel's electrical system. At a port, rail ramp or container yard it plugs into a reefer point. On the road it runs from a diesel generator set. Whenever it has power, it holds the set point the shipper booked, heating or cooling as needed.
Reefers carry anything that has to stay within a temperature range: fresh produce, meat, seafood, dairy and frozen food, pharmaceuticals and medical products, some chemicals, and goods that must not freeze in winter.
Reefers come in the same lengths as dry containers. The 40ft high cube is by far the most common, and the 20ft is used for dense cargo that reaches the weight limit first. Because the walls are thicker and the refrigeration unit takes space at one end, a reefer has less room inside than a dry container of the same size.
| Container | Inside (L × W × H) | Capacity | Max payload |
|---|---|---|---|
| 20ft reefer | 5.44 × 2.29 × 2.27 m | 28.3 m³ | 27,400 kg |
| 40ft reefer | 11.56 × 2.28 × 2.25 m | 59.3 m³ | 27,700 kg |
| 40ft high cube reefer | 11.58 × 2.29 × 2.40 m | 67.3 m³ | 29,520 kg |
Representative specifications. Dimensions and payload vary by container owner, manufacturer and age, so confirm with the shipping line for a specific booking. Road weight limits often allow less than the container's maximum payload.
Most reefer units hold a set point between about -30 °C and +30 °C. The shipper gives the set point on the booking, and the line programs it during the pre-trip inspection before the container is released.
Temperature is not the only setting. Fresh produce keeps breathing after harvest, so the fresh-air vent is opened to a set exchange rate to clear the gases it gives off. Humidity can be controlled on most modern units, and controlled atmosphere containers also adjust oxygen and carbon dioxide to slow ripening.
| Cargo | Typical set point | Notes |
|---|---|---|
| Frozen food, meat and seafood | -18 °C or colder | Vent closed. Can be stowed tightly, because the air only needs to flow around the load. |
| Chilled meat and dairy | About -1 °C to 4 °C | Vent usually closed. Air must flow through the cargo. |
| Fresh produce | About 0 °C to 13 °C | Depends on the commodity. Vent open to the rate the produce needs. |
| Pharmaceuticals | 2 °C to 8 °C, or 15 °C to 25 °C | Set by the product's label. Data loggers are standard. |
| Freeze-sensitive goods in winter | Above freezing | The unit heats to hold the set point in cold weather. |
Set points are examples. Use the temperature the product's owner or label specifies, and write it on the booking and the bill of lading.
Most reefers blow cold air in along the floor, through a T-shaped grated floor, and draw it back across the top of the cargo. The load has to let that air reach every part of it. Most cold-chain damage comes from loads that block the air path, not from units that fail.
Bring the goods to the carriage temperature before loading. A reefer holds temperature but is not built to pull warm cargo down.
Cargo above the load line marked on the walls blocks the return air path at the top of the box.
Do not cover the floor channels with plastic sheets or solid pallets, and do not leave large gaps where air can bypass the load.
Cartons with vent holes, lined up on the pallet, let air rise through the load. Frozen cargo can be stowed tightly.
Put the set point, vent setting and humidity on the booking and the bill of lading, and add a data logger for anything high-value.
Load from a cold dock if possible and keep the doors open for as little time as possible.
Once the container is off the ship, it needs power for every hour of the inland move. At the terminal it is plugged into a reefer point, which usually carries a daily plug-in and monitoring charge. For the road leg it needs a genset, either clipped onto the container or slung under the chassis, so the container drayage has to be booked with genset-equipped equipment.
Reefer containers also travel inland by rail from Vancouver, Prince Rupert, Montreal and Halifax, with gensets for the journey. For long moves into the interior, the cargo is often transloaded at the port into a 53-foot reefer trailer, which returns the empty container to the line sooner and runs the rest of the way as a regular truckload.
We book reefer containers with ocean carriers through our partners, arrange genset drayage from the port or rail ramp, and transload into reefer trailers when the freight is going further inland, with dispatch watching the load 24/7.
Reefer trailers across Canada and the US for chilled and frozen freight.
Read more →FCL and LCL containers to and from major ports, booked through our partners.
Read more →Containers moved between the port or rail ramp and your dock.
Read more →Food freight that has to arrive at the right temperature and on time.
Read more →Fresh produce kept cold from farm to dock.
Read more →Duties, landed cost and the documents for goods coming in.
Read more →A reefer container is a refrigerated shipping container. It is a standard ISO container with insulated walls and a built-in electric refrigeration unit at one end that holds the cargo at a set temperature, powered by the ship, the terminal or a generator on the road. Reefers carry fresh produce, meat, seafood, dairy, frozen food, pharmaceuticals and other temperature-sensitive goods.
Most modern reefer units hold a set point between about -30 °C and +30 °C. Frozen food usually travels at -18 °C or colder, chilled produce between about 0 °C and 13 °C depending on the commodity, and many medicines at 2 °C to 8 °C. Specialised super-freezer containers go to around -60 °C for products such as sashimi-grade tuna.
A 40ft high cube reefer, the most common size, is about 11.58 m long, 2.29 m wide and 2.40 m high inside, with roughly 67 cubic metres of space and a payload near 29,500 kg. A standard-height 40ft reefer has about 59 cubic metres. Exact figures vary by container owner and age.
A 20ft reefer is about 5.44 m long, 2.29 m wide and 2.27 m high inside, with roughly 28 cubic metres of space and a payload near 27,400 kg. It is the size to use for dense, heavy cargo such as frozen meat, where the weight limit is reached before the space runs out.
Yes. A reefer holds a set point, not just a low temperature, so in cold weather the unit heats the cargo to stop it falling below the set point. That is why reefers are also used in a Canadian winter for goods that must not freeze.
Not reliably. A reefer is built to keep cargo at its temperature, not to pull warm cargo down to it. Goods should be pre-cooled to the carriage temperature before loading. Loading warm produce into a reefer is one of the most common causes of cold-chain claims.
On the road the refrigeration unit runs on a diesel generator set, or genset. It is either clipped onto the front of the container or mounted under the chassis. At ports, rail ramps and container yards the container is plugged into a reefer power point instead.
PTI stands for pre-trip inspection. The shipping line or depot tests the refrigeration unit, sets the temperature, ventilation and humidity from the booking, and confirms the container holds temperature before it is released to the shipper. Ask for a PTI'd container when you book.
Controlled atmosphere, or CA, adjusts the oxygen and carbon dioxide levels inside the container as well as the temperature. Lower oxygen slows ripening, which extends the shelf life of produce such as avocados, bananas and berries on long voyages. It is booked as a separate container type.
A reefer container is an ISO box that travels by ship, rail and truck and gets its power from outside. A reefer trailer is a road trailer, usually 53 feet in North America, with its own diesel refrigeration unit. Imported reefer containers are often transloaded into reefer trailers at the port for long inland moves.
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