Refrigerated box truck: payload, reefer units and what the cold costs you

A refrigerated box truck moves food, flowers and medicine at a set temperature, on routes too short or too local for a reefer trailer. It is a dry box truck with three things added: insulation in the walls, roof and floor, a refrigeration unit, and the responsibility to prove the temperature held. Each of those costs something. This guide puts numbers on the cost in payload and in cooling capacity, using a rental fleet's and a unit maker's published specs, and covers the rules and the checks for buying used.

How a refrigerated box truck is built

• Insulated box: foam-insulated walls, roof, floor and doors, with a washable liner. The insulation takes some inside space and adds weight.
• Refrigeration unit: usually mounted on the front wall of the box above the cab ("nose-mounted"), with an evaporator inside. Penske lists a nose-mounted reefer/freezer unit on its 18 to 26 ft refrigerated trucks.
• Power: a self-powered diesel unit, or a unit driven from the truck's engine. Some units add electric standby so they can run plugged in while parked.
• Controls and records: a controller to set the temperature and, often, a recorder to log it.

SOURCE:Penske Truck Rental, OCT 2026;Thermo King, OCT 2026

What going refrigerated costs in payload

Penske rents both a dry and a refrigerated truck in the 26 ft class, at the same rating:

SOURCE:Penske Truck Rental, OCT 2026;Penske Truck Rental, OCT 2026

Up to 2,000 lb less payload and up to 100 cubic feet less space, from the unit, insulation and liner. The unit alone is heavy: Thermo King lists its T-590 straight-truck unit at 910 lb, or 973 lb with electric standby.

SOURCE:Thermo King, OCT 2026

Both trucks stay at 26,000 lb, so neither needs a CDL; the refrigeration comes out of payload, not the rating.

SOURCE:eCFR, 49 CFR 383.5, OCT 2026

Capacity falls as the box gets colder

A refrigeration unit's cooling capacity is quoted at a box temperature, and it drops as that temperature drops. Thermo King publishes capacity for its straight-truck units at three temperatures:

SOURCE:Thermo King, OCT 2026;Thermo King, OCT 2026

That is the real difference between a refrigerated box truck and a freezer box truck. A unit sized comfortably for fresh produce at 35 F has roughly a third to a half of that capacity left at -20 F. A box truck with freezer duty needs a bigger unit, better insulation, or both, and fewer door openings per route. If you plan to haul frozen loads, ask the unit maker or upfitter to size the unit for your box length, insulation and door openings at the coldest setpoint you will run.

On electric standby, capacity is lower again: Thermo King lists the T-890 at 21,000 BTU/hr at 35 F on electric, against 25,000 on the engine.

SOURCE:Thermo King, OCT 2026

Insulated vs refrigerated vs climate controlled

"Climate controlled" can mean a unit that heats as well as cools to hold a range in any season. Ask what range the unit is rated to hold, whatever it is called.

The food safety duties that come with it

Hauling food in a refrigerated box truck brings federal sanitary transportation duties, unless an exemption in the rule applies to your operation. Under the FDA rule, the shipper must specify the required temperature in writing, the carrier must pre-cool the box when the shipper requires it, and the carrier must be able to show that the temperature was kept during transport, if the shipper asks.

SOURCE:eCFR, 21 CFR 1.908 (FDA), OCT 2026

In practice: pre-cool before loading, keep the reefer running and the doors closed, and keep the temperature records your shipper or broker expects. Our reefer box truck loads guide covers the paperwork side of booking cold freight.

26 foot refrigerated box truck

The 26 ft size tops Penske's non-CDL refrigerated range: up to 1,600 cubic feet and 8,000 lb, with a liftgate for deliveries without docks. On a 26 ft box truck refrigerated for dense loads, payload will run out before space; if they are light and bulky, the opposite. A 26' refrigerated box truck on a heavier chassis rated over 26,000 lb carries more, and needs a CDL driver.

SOURCE:Penske Truck Rental, OCT 2026;eCFR, 49 CFR 383.5, OCT 2026

Sizes are compared on the box truck sizes chart; chassis classes in medium duty box truck. An electric chassis with a reefer body is possible too, and range matters more with a unit drawing power; see electric box truck.

Buying a used one

1. Unit hours and service records. Ask for both, and who did the work.
2. Pull-down test. Run the unit from ambient to your coldest setpoint with the doors closed and time it.
3. Hold test. Leave it at setpoint and watch whether it holds.
4. Insulation and liner. Look for wet spots, soft panels, punctures and delamination.
5. Doors and seals. Gaskets, hinges, latches and any strip curtain.
6. Floor and drains. Rot, cracks and blocked drains.
7. Records and recorder. A working temperature recorder and the ability to download logs.

Our used box truck guide covers the chassis side, and box truck reefer unit the unit itself. The truck size calculator checks loads against box size.

SOURCE:Penske Truck Rental, OCT 2026;Penske Truck Rental, OCT 2026;Thermo King, OCT 2026;Thermo King, OCT 2026;eCFR, 21 CFR 1.908 (FDA), OCT 2026;eCFR, 49 CFR 383.5, OCT 2026

Questions box truck owners ask

Q-01What is the difference between a refrigerated and a freezer box truck?

The setpoint the unit can hold under load. A refrigerated truck keeps fresh goods cool, around 35 F; a freezer box truck holds frozen goods well below 0 F. The same unit delivers far less cooling at freezer temperatures, so a box truck freezer needs a unit and insulation sized for the cold rather than the chill.

Q-02Is an insulated box truck the same as a refrigerated one?

No. An insulated box truck has insulated walls but no refrigeration unit, so it slows temperature change but cannot hold a setpoint. It suits short runs with pre-chilled goods or ice. A refrigerated box truck adds a unit that actively holds the temperature for the whole trip.

Q-03How much can a 26 ft refrigerated box truck carry?

Penske lists up to 8,000 lb of payload for its 18 to 26 ft refrigerated truck, rated up to 26,000 lb GVW with up to 1,600 cubic feet. Its dry 22 to 26 ft box lists up to 10,000 lb on the same rating. The unit, insulation and liner take the difference.

Q-04What should I check on a used refrigerated box truck?

The unit's hours and service records, a pull-down test to your setpoint with the doors closed, door seals and gaskets, the insulation for wet or damaged spots, the floor and drains, and any temperature recorder or download records. A refrigerated box that cannot pull down or hold temperature is a dry box with a heavy unit on it.

Q-05What is an ice box truck?

An informal name some people use for a refrigerated or insulated box truck. Ask what it actually has: an insulated box alone, or an insulated box with a working refrigeration unit, and at what temperature that unit is rated to hold a load.