Reefer Container Basics for Temperature-Controlled Shipping

01What Is a Reefer Container

A reefer container has a built-in refrigeration unit that holds the internal temperature within a set range. It’s used for fresh and frozen food, pharmaceuticals, chemicals, and any other cargo that can’t tolerate ambient temperature swings during transit.

Three things make it a different piece of equipment from a dry container, not just a colder version of one.

Less usable space. The refrigeration machinery and insulated walls eat into the interior dimensions, so a 40ft reefer holds noticeably less cargo by volume than a 40ft dry container of the same footprint.

It needs continuous power. The unit has to stay plugged in at the container yard, on the vessel, and on the chassis during inland moves. Any gap in power is a gap in temperature control.

It costs more to move. Equipment sourcing, electricity, and monitoring all add cost on top of the base freight, so reefer rates run well above dry container rates for the same route.

02Setting the Temperature and Stowing the Load

The right setpoint depends entirely on the commodity. Frozen goods commonly run around −18°C and chilled goods around 0–5°C, but the exact figure is not something the carrier decides — the shipper has to specify the correct setpoint for the product being shipped.

The point that catches first-time shippers out: a reefer unit is built to hold a temperature, not to bring cargo down to one. Loading warm product and expecting the unit to chill it during transit means a slow pull-down period during which quality can already be compromised. Cargo should be pre-cooled to the target temperature before it goes into the container.

Stowage matters just as much as the setpoint. The refrigerated air has to circulate, so the T-shaped floor channels (T-floor) must stay clear, cargo shouldn’t be packed to the ceiling, and boxes shouldn’t be jammed tight against the side walls. Blocked airflow creates uneven temperatures inside the same box.

03What to Confirm When Booking

Equipment availability. Reefer units are a smaller pool than dry containers. On thinner routes, book earlier than you would for a dry box.

Power confirmation. Plug-in points at the container yard and reefer plugs on the vessel are both limited in number. Confirm at booking time that a slot is actually reserved, not just requested.

Temperature recording. Reefer units log temperature history through the voyage. That log becomes the key evidence if a quality claim comes up later, so confirm in advance how to retrieve it and in what format.

Our own operation is built around dry 40HC containers, so if your cargo needs a reefer, flag it as early as possible when you reach out — we’ll walk through equipment and routing options together.

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