Introduction to Reefer Trucks
If you run perishables, you’ve already bumped into the question what is a reefer truck—and why shippers obsess over setpoints, seals, and signatures. In short: a reefer is a refrigerated vehicle designed for temperature-controlled transport. It protects perishable goods inside a sealed, insulated cargo area by using a dedicated refrigeration unit (the “reefer unit”) that regulates temperature control, humidity control, and airflow control, and proves it with data loggers, telemetry sensors, and setpoint tracking. Done right, reefers knit together the cold chain logistics that move food, vaccines, and other temperature-sensitive cargo through the supply chain without breaking spec.
Insider note: the biggest difference from a dry van isn’t “blowing cold air”—it’s documentation. Shippers pay a premium for verifiable cargo monitoring, clean trip reports, and zero drama at the dock.
Components of a Reefer Truck
Refrigeration System
A modern cooling system combines compressor, condenser, evaporator, expansion device, and high-efficiency fan motor assemblies. Controllers compare live cargo temperature to thermostat settings and modulate capacity. Multi-compartment trailers use zone cooling to run, say, lettuce at +3 °C while frozen goods sit at −18 °C. Good units expose alarms to the cloud for cold chain analytics, helping you catch trends (recurring warm spikes after Stop #3) and plan reefer retrofits (e.g., stronger door seals).
Refrigerant types matter, too. Many fleets have shifted from R-404A toward lower-GWP blends such as R-452A, and some are piloting CO₂ (R-744) systems or partial electrification with an electric reefer architecture. In California, newly manufactured TRUs must use refrigerant GWP ≤ 2,200; fleets face a staged turn-over to zero-emission truck TRUs culminating by December 31, 2029.
Insulation and Construction
Insulation does the quiet heavy lifting. Reefers use high R-value insulation panels, vapor-tight barrier insulation, and rugged insulated walls with tight door gaskets. Floor channels and bulkheads preserve airflow control; quality cargo insulation details keep hot spots from forming. Better thermals = less compressor work = better fuel efficiency.
Types of Reefer Trucks
Semi-Trailer Reefers
The long-haul workhorse is the 48–53-ft semi-trailer refrigerated trailer. It’s dock-friendly, easy to stage in cold storage, and can be built as single- or multi-temp for mixed refrigerated freight.
Straight Truck Reefers
Urban refrigerated delivery lives on straight truck bodies: tight turning, fast door-open cycles, and great for route density. Think regional grocers, meal kits, bakery, florals.
Applications of Reefer Trucks
Food and Beverage Industry
Food transport depends on uninterrupted spec: dairy 1–4 °C, berries near 0–1 °C (unless chilling-sensitive), proteins just above their freezing point, and deep-frozen items at −18 °C or colder. For retail/foodservice, the U.S. FDA Food Code cold-holding rule anchors at ≤ 5 °C / 41 °F; trip records plus receiving thermometers make the QA team breathe easier.
Pharmaceutical Transport
Pharmaceutical shipping demands tighter tolerances and auditable trails (e.g., +2…+8 °C vaccines; 15…25 °C for certain APIs). EU GDP guidance expects controls proportionate to risk—planning routes, monitoring, and investigating excursions—rather than a one-size-fits-all setup. For vaccines, WHO/CDC toolkits remain the baseline for pack-out and verification.
Benefits of Using Reefer Trucks
Extended Shelf Life
Stable temps preserve flavor, texture, safety, and product stability—directly reducing claims and shrink. That’s real money, plus happier buyers.
Compliance with Regulations
Between FSMA/GDP, retailer SOPs, and buyer audits, compliance is table stakes. Clean setpoint tracking, defrost cycle logs, and data loggers tied to shipment IDs make inspections routine, not stressful. (FSMA 204 traceability is the next big documentation wave; see “Fresh 2025 Updates” below.)
Maintenance and Operational Considerations
Regular Maintenance
A disciplined reefer maintenance program catches coolant leaks, tired belts, electrical gremlins, and slipping fan motor efficiency before they strand a load. Thermo King’s current EMEA guidance illustrates a practical cadence:
| Service | Interval | Examples of tasks |
| A Service | Every 1,500 hours or 12 months | Pre-trip checks, leak/fastener inspection, belts, obvious wear. |
| B Service | Every 3,000 hours or 24 months | Deeper PM: filters, electrical connections, controller review. |
| C Service | Every 9,000 hours or 72 months | Major inspection and service per model specification. |
Source: Thermo King e-Tech manual excerpt, updated March 11, 2025.
Also calibrate telemetry sensors and data loggers, test battery backup for monitors, and inspect door seals and panels (don’t let pinholes rob your R-value insulation).
Fuel Efficiency
Spec and habits matter. Tight boxes, clean coils, sane thermostat settings, and disciplined doors reduce runtime. Typical modern units burn roughly 0.4–1.1 gal/hr when running; smarter modes, shore power, and zoning keep fuel in the tank.
Add route optimization and avoid unnecessary engine idling at the dock—especially if you can plug an electric reefer into standby.
Tables & Quick-Reference
A. Commodity Setpoint Cheat Sheet (typical bands — always follow shipper SOP)
| Commodity group | Common transport setpoint | Notes / sources |
| Leafy greens / berries | 0–3 °C (32–37 °F) | Cold, high humidity; sensitive to warm door time. FDA cold-holding ≤ 5 °C still applies at receipt. |
| Meat & seafood (fresh) | −1…+2 °C (30–36 °F) | Load pre-chilled; trailers pre-cool (doors closed) before loading. |
| Chilling-sensitive produce (citrus, cucumbers, etc.) | 7–10 °C (45–50 °F) for short-haul | UC Davis compatibility chart for short-term transport. |
| Frozen foods | −18 °C (0 °F) or colder | Use continuous mode or tight cycle swing. |
| Vaccines (common) | +2…+8 °C | GDP/WHO/CDC guidance; verify device calibration. |
B. Refrigerants & GWP (selection)
| Refrigerant | Typical use | 100-yr GWP (AR4/AR5/AR6 refs) | Notes |
| R-404A | Legacy TRUs | ≈ 3,922 | High-GWP HFC; phase-down pressure globally. |
| R-452A | Newer TRUs (drop-in for 404A) | ≈ 2,140 | ~45% lower than 404A; still above many future thresholds. |
| R-744 (CO₂) | Emerging TRUs / intermodal | 1 | Very low GWP; different pressure regime/architecture. |
Policy context: The EU’s revised F-gas Regulation (EU) 2024/573 steepens HFC phase-down and widens leak-prevention rules; California adds caps and zero-emission milestones for truck TRUs.
C. Loading & Airflow — the Non-Negotiables
| Step | Why it matters | Pro tip |
| Pre-cool the trailer | Removes heat from box/liners so product isn’t the “coolant.” | Pre-cool with doors closed; meat guidance calls for aggressive pre-chill before loading. |
| Pre-cool the product | Warm loads overwhelm capacity. | Stage freight in cold storage transport to target core temps before loading. |
| Respect return-air space | Blocked vents cause warm pockets. | Keep pallets off the front wall & under ceiling channels for airflow control. |
| Use curtains/partitions for zones | Limits temp loss when doors open. | Combine zone cooling with clear placards and probe locations. |
| Logger placement | Catch worst-case temps, not best-case. | Put data loggers high-rear & center-mass; audit defrost cycle and door events later. |
Types of Reefer Trucks (Deep Dive)
Semi-Trailer Reefers
Long-haul refrigerated shipping wins on cube and flexibility. Multi-temp models (single chassis, separate evaporators) support mixed refrigerated cargo and refrigerated freight on the same run, and can pair with intermodal legs via refrigerated shipping container handoffs.
Straight Truck Reefers
For dense city routes and frequent stops, straight trucks reduce door-open time and out-of-route minutes. They’re ideal for bakery/dairy/produce where extended shelf life hinges on quick turns and clean proofs.
Benefits of Using Reefer Trucks (Operational)
Extended Shelf Life
Stable temps, smart humidity control, and proper airflow control slow enzymatic activity and bacterial growth. That’s fewer claims, tighter forecasting, and happier receivers.
Compliance with Regulations
Strong paper trails—setpoint tracking, data loggers, alarm logs—make audits routine. When you can show compliance and “no significant excursions,” the conversation shifts from penalties to process.
Insider Playbook: Fresh 2025 Updates Fleet Managers Actually Care About
- California TRU rule (real-world impact): Starting Dec 31, 2023, owners must convert 15% of truck TRUs to zero-emission each year; all truck TRUs operating in CA must be zero-emission by Dec 31, 2029. Newly manufactured TRUs must use low-GWP refrigerants (≤ 2,200). Budget for infrastructure and charging windows at DCs.
- EU F-gas (2024/573): Adopted Feb 7, 2024; applies from Mar 11, 2024. Expect tighter quotas, stricter leak control, and more paperwork across borders. If you still buy high-GWP blends, expect price volatility.
- FSMA 204 traceability: Original U.S. compliance date Jan 20, 2026; FDA proposed in Aug 2025 to push the date ~30 months (to July 20, 2028). It doesn’t change what data is required—just when. Align your TMS/telematics now.
- Telematics gets standard-issue: Thermo King now ships TracKing® as standard on many units in North America (remote temp reports for FSMA, alarms, fuel, door events). Carrier Transicold’s Lynx Fleet™ added a 2025 mobile app and new module with backup power and dual cellular/satellite links—handy when trailers sit unpowered. Link each platform once to keep buyers happy: Thermo King TracKing • Carrier Lynx Fleet.
Maintenance and Operational Considerations (Fuel & Runtime)
Fuel Efficiency
A quick, realistic modeling snapshot:
| Scenario | Ambient | Mode | Door time / hr | Expected burn (guidance) |
| Frozen, linehaul | 20 °C (68 °F) | Cycle | 2 min | ~0.4–0.6 gal/hr |
| Fresh produce, summer | 32 °C (90 °F) | Continuous | 8–10 min | ~0.8–1.1 gal/hr |
| Multi-stop dairy | 25 °C (77 °F) | Continuous | 12–15 min | ~1.0–1.3 gal/hr |
Ranges compiled from fleet advisories and vendor guidance; your spec/insulation and handling will swing results.
Operational levers that move the needle
- Tighten doors and seals; keep coils clean; verify fan motor efficiency.
- Use shore power/standby where available (especially with an electric reefer).
- Train loaders to preserve channels; never block return air.
- Align route optimization with thermal behavior (front-load warmest stops, shorten door-open windows).
Types of Reefer Trucks (Intermodal & Alternatives)
- Refrigerated shipping container (intermodal): handoff from ocean/rail to drayage; plug-in power at yards; great for lane flexibility.
- Light-duty vans: emerging thermoelectric cooling pilots for micro-fulfillment; good for short distances and tight delivery windows.
Conclusion
At its best, a reefer operation is a choreography of equipment, process, and proof. From high-R-value insulation, vapor-tight barrier insulation, and tuned refrigeration unit controls to disciplined loading, verified defrost cycle behavior, and accurate data loggers, every piece points to the same outcome: refrigerated transport that keeps perishable freight in spec, satisfies auditors, and delights receivers.
If you came here asking what is a reefer truck because a buyer demanded proof, the answer is part physics, part paperwork. Spec the right refrigerated truck or trailer, treat your insulated cargo area like a lab, build SOPs that minimize engine idling and door-time, document everything, and use cold chain analytics to improve. Do that, and you’ll move refrigerated cargo more safely, more efficiently, and more profitably—load after load.
FAQ (fast)
Q: What is a reefer truck vs. trailer?
A straight-truck refrigerated delivery box vs. a semi-trailer refrigerated trailer. Same principles; different use cases.
Q: Do I need three temp zones?
Only if you routinely mix fresh and frozen goods or run divergent specs. Otherwise, single-temp plus strong SOPs is simpler.
Q: What about refrigerant bans?
EU F-gas (2024/573) accelerates HFC phase-down; CA requires lower-GWP in new TRUs and a zero-emission path. Start planning for changes to refrigerant types and powertrains now.
Compliance & Source Notes
- FDA Food Code 2022 – cold holding ≤ 5 °C / 41 °F.
- USDA FSIS/AMS transport guidance – pre-cooling practices; heat-load basics.
- EU GDP/WHO/CDC – pharma/vaccine transport expectations.
- CARB TRU amendments & zero-emission schedule – fleet turnover and low-GWP refrigerant requirement.
- EU F-gas 2024/573 – adoption and scope.
- EPA GWP reference – values for R-404A and R-452A. CO₂ GWP=1 from national regulators.
