A refrigerated trailer — universally called a "reefer" — is a dry van with a self-contained diesel-powered refrigeration unit (typically a Thermo King or Carrier brand unit) mounted on the nose. The insulated box and mechanical refrigeration allow precise temperature control across a wide range, typically from -20°F up to +70°F, making reefer the essential equipment for any freight that must stay cold from origin to destination. The interior dimensions are slightly smaller than a comparable dry van due to the insulated wall and floor panels, which are typically 4–5 inches thick on each side. Interior width is usually around 98 inches, and usable height is approximately 105 inches. Payload capacity is also reduced — the refrigeration unit, insulation, and heavier structural components add roughly 3,000 lb to the trailer tare weight compared to a dry van. Temperature management is the defining operational challenge. Shippers and carriers must agree on setpoints, pre-cooling requirements, and continuous monitoring protocols. FSMA (the FDA Food Safety Modernization Act) imposes Sanitary Transportation requirements on carriers hauling human food, including documentation of training, equipment adequacy, and temperature records. Non-compliance can result in FDA enforcement action and shipper-imposed carrier disqualification. Pharmaceutical and biotech shippers apply even more rigorous standards. GDP (Good Distribution Practice) guidelines require validated temperature-controlled lanes, excursion response procedures, and qualification data for both equipment and lanes. Because of higher equipment, fuel, and maintenance costs — plus specialized compliance requirements — reefer rates are consistently above dry van rates on comparable lanes. Seasonality matters: spring produce season and summer peak can tighten reefer capacity significantly in agricultural corridors.
| Typical length | 48–53 ft |
| Typical width | 8.5 ft (102 in) |
| Typical height | 13.5 ft exterior; ~105 in interior (insulated walls reduce interior width to ~98 in) |
| Payload capacity | Up to 43,000 lb (refrigeration unit adds ~3,000 lb of tare weight vs. dry van) |
New 53 ft refrigerated trailers typically range from $75,000–$110,000 depending on insulation spec and reefer unit brand (Thermo King, Carrier). Per-mile rates are typically 15–25% above comparable dry van lanes.
Most modern reefer units can maintain setpoints from approximately -20°F to +70°F. Frozen loads (typically -10°F to 0°F), fresh/chilled loads (34°F–38°F), and "protected" loads (above freezing but below ambient) are the three main categories. Always confirm equipment capability with the carrier before booking.
The FDA's FSMA Sanitary Transportation Rule (21 CFR Part 1, Subpart O) requires carriers transporting human food in temperature-controlled trailers to follow specific practices around equipment cleanliness, temperature control, and training. It applies to motor carriers hauling food for human consumption in refrigerated vehicles. Certain small carriers and non-refrigerated exempt loads have exceptions — consult 21 CFR Part 1.900 for full applicability.
The refrigeration unit has its own diesel engine and fuel tank, separate from the tractor. The reefer unit fuel tank is typically 50–100 gallons. Carriers factor in 2–4 gallons per hour of reefer fuel consumption when calculating cost. Some shipper facilities and truck stops offer shore power ("plug-in") connections for trailer-only dwell time.
Yes, in many cases. Shippers often use reefer trailers for ambient loads when dry van capacity is tight — the trailer can run with the unit off. However, the reduced interior dimensions and lower payload capacity (vs. dry van) are trade-offs, and reefer rates are typically higher even for ambient loads.
Common causes include: inadequate pre-cooling before loading, loading warm product directly into a cold trailer, damaged door seals, blocked return-air chutes, improper airflow around pallets, refrigerant issues, and belt or compressor failures. Continuous temperature loggers placed inside the load (not just at the reefer unit sensor) are recommended for sensitive freight.