Many fleets already run a telematics system — GPS tracking, driver behaviour, fuel, route optimisation, and often a temperature read-out from the refrigeration unit. So a fair question is: if telematics already shows temperature, why add a dedicated cold chain monitoring system?
The answer is a difference in purpose. Telematics is designed for managing vehicles; cold chain monitoring is designed for proving the condition of regulated goods. They answer different questions, and in regulated cold chains you usually need both.
Where vs what
The cleanest way to see the difference is the questions each system answers. Telematics answers: where is the vehicle, is the reefer unit running, what route did we take, how long was the stop. Cold chain monitoring answers: what condition are the goods in, is the product within spec, was there an excursion event, can we prove compliance to an auditor.
Why reefer-unit temperature isn't product-space proof
A refrigeration unit's built-in sensor reports the unit's return-air temperature, not the temperature where the product actually sits — which can differ across compartments, near doors, and with load. For regulatory evidence the gaps usually are:
- Sensor placement measures the unit, not the product space.
- Unit sensors are rarely calibrated or traceable for audit purposes.
- No GDP-style audit trail or 21 CFR Part 11 data integrity.
- Alerts (if any) without a documented deviation workflow.
- Vehicle-level data only — no shipment- or compartment-level proof.
Complement, don't replace
This is not an either/or. Telematics should keep doing what it does well — fleet operations. A dedicated monitoring system adds the compliance layer on top: calibrated, EN 12830-certified sensors in the product space, per-zone and per-shipment records, deviation handling, and audit-ready reporting. The two can integrate so monitoring data flows into your fleet dashboards.
The message is simple: keep telematics for the vehicle; add cold chain monitoring for the goods.
Multi-compartment and multi-temperature loads
The gap is widest on mixed loads. A vehicle carrying frozen, chilled and ambient goods at once cannot prove each band held from a single reefer-unit reading. Product-space monitoring places a sensor in each compartment, so frozen stays demonstrably below its limit while chilled holds 2–8 °C — each with its own record and alarm profile. That per-zone evidence is exactly what GDP Chapter 9 and EN 12830 reviewers expect, and it is what telematics-only setups cannot produce.
Questions worth asking
If you're relying on telematics temperature for compliance, these questions usually expose the gap:
- Does the system provide EN 12830-certified, calibrated temperature data?
- How do you prove to an auditor that the actual products stayed in range?
- When there's an excursion, who is notified and how is the deviation documented?
- Can you produce calibration certificates for the temperature sensors?
Key takeaways
- Telematics manages vehicles; cold chain monitoring proves goods condition.
- Reefer-unit temperature is return-air, not calibrated product-space data.
- Compliance needs calibrated sensors, audit trail, and deviation handling — telematics rarely has these.
- Mixed frozen/chilled/ambient loads need per-compartment proof a single unit reading cannot give.
- Best practice is to complement telematics with a monitoring layer, not replace it.