August 30, 2026
Reefers: the cold chain does not pause at the terminal gate
A refrigerated container is a machine, and a machine needs power. Inside the terminal it is plugged in. On the road it is not, so it runs on a genset, and whether one is arranged is the difference between a delivery and a claim. Reefers also carry less than a dry box of the same outside size, because the insulation and the machinery take real space, and they accrue the same per diem as any other container while the empty waits to go back.
Plugged in, then not
In the terminal a reefer sits on a plug and its temperature is monitored. The moment it comes off that plug for the road leg, the cooling has to come from somewhere else, and that somewhere is a genset: a diesel generator that travels with the box.
This is arranged, not assumed. A reefer collected without a genset is a well-insulated box slowly warming up, and insulation buys hours, not days.
So the reefer question at booking is never just whether a carrier moves reefers. It is whether the genset is arranged, fuelled and running for the whole leg, including any time the box spends on a yard.
The set point belongs to the shipper, not the truck
The temperature is set by whoever knows the cargo, and it should arrive with the booking rather than be guessed at the gate. Frozen and chilled are different regimes and the difference is not a rounding error.
Ventilation matters too on produce, because respiring cargo behaves differently from frozen cargo, and the setting that suits one can damage the other.
The correct instruction is written down and travels with the move. Anything agreed verbally about a temperature is exactly the kind of detail that a claim later turns on.
What a reefer costs you that a dry box does not
Payload. The insulation and the machinery occupy real space and weight, so a reefer carries meaningfully less than a dry container of the same external size. If you plan a load on dry-box numbers you will be short.
Time, in the way that costs money. Reefers are on a clock in two senses at once: the cargo's own tolerance, and the shipping line's per diem, which runs from gate-out until the empty is returned exactly as it does for a dry box.
And handling. Fewer facilities can receive a reefer properly, which narrows the options when a delivery slips and makes planning the receiving end more important than it is for dry freight.
How to make a reefer move boring
Send the temperature, the ventilation setting if any, the commodity and the receiving hours with the booking, along with the container number and the terminal.
Book the delivery for a window the receiver can genuinely keep. A reefer waiting at a closed dock is the worst version of detention, because the clock that matters is the cargo's rather than the invoice's.
And decide early whether the freight is going a long way inland. Past a certain distance, transloading into a refrigerated trailer returns the line's box early and stops the per diem, and that decision is much cheaper made at quote time than at the dock.
Reefer · Genset · Cold chain · Per diem · Perishables
Where this comes from
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Questions
Straight answers
Does a reefer container need a genset on the road?
Yes. Inside the terminal a reefer sits on a plug and its temperature is monitored. The moment it comes off that plug for the road leg the cooling has to come from somewhere else, and that somewhere is a genset, a diesel generator that travels with the box. It is arranged, not assumed. A reefer collected without one is a well-insulated box slowly warming up, and insulation buys hours, not days.
Who sets the temperature on a reefer container?
Whoever knows the cargo, which is the shipper rather than the truck. The set point should arrive with the booking rather than be guessed at the gate, because frozen and chilled are different regimes and the difference is not a rounding error. Ventilation matters too on produce, since respiring cargo behaves differently from frozen cargo and a setting that suits one can damage the other. Write it down, because a claim later turns on exactly that detail.
Does a reefer carry less than a dry container of the same size?
Meaningfully less. The insulation and the machinery occupy real space and weight, so the usable payload inside a reefer is smaller than inside a dry box of the same external dimensions. If you plan a load on dry-box numbers you will be short, and you will find out at the worst moment. Plan the cargo against reefer figures from the start, and confirm them for the specific box rather than assuming a class average.
Does per diem run on a reefer container?
It does, exactly as it does for a dry box. A reefer is on two clocks at once: the tolerance of the cargo itself, and the shipping line per diem, which runs from gate-out until the empty is returned. Handling is a third pressure, since fewer facilities can receive a reefer properly, which narrows your options when a delivery slips and makes planning the receiving end more important than it is for dry freight.
When should reefer cargo be transloaded into a trailer?
Past a certain distance inland. Transferring the cargo into a refrigerated trailer returns the shipping line box early and stops the per diem, and that decision is far cheaper made at quote time than at the dock. Decide it before the box moves rather than after. Book the delivery for a window the receiver can genuinely keep as well, because a reefer waiting at a closed dock is the worst version of detention there is.
How do I get a rate?
Send the lane, the equipment, the container size and the port, and we come back with a number. Quotes and dispatch run 24 hours a day at quotes@dariaslogistics.com.