Data loggers for temperature and humidity: how do you choose?
A data logger records values such as temperature and humidity over time, making the climate in storage, transport and the EPA traceable. Selection comes down to measured quantities, sampling interval, memory, battery life, readout, accuracy and alarm thresholds - weighted differently for each application.
View measurement toolsWhat is a data logger and what does it record?
A data logger is a measuring device that captures and stores physical quantities automatically at fixed time intervals. Temperature and relative humidity are the most common; depending on the model it may also record dew point, CO2, pressure, light or shock. The result is a continuous time series rather than isolated snapshots.
The advantage over a single hand-held reading is continuous monitoring: the logger works unattended for hours, days or months and captures events at night, inside a sealed transport container or over the weekend. The values can later be viewed as a curve and archived as evidence.
Typical fields of use are monitoring storage climate, the cold chain and transport, as well as the climate in an ESD protected area, where temperature and humidity affect static charging and the shelf life of moisture-sensitive devices. More on the individual quantities at /en/ratgeber/temperature-measurement and /en/ratgeber/humidity-measurement.
Which criteria decide the choice?
The right logger depends on the application and the documentation requirement. Seven criteria form the backbone of the choice: which quantities are measured, how often, how long they are stored, how long the battery lasts, how they are read out, and how accurate and traceable the values must be.
| Criterion | What to watch | Why it matters |
|---|---|---|
| Measured quantities | temperature, humidity, dew point or CO2 | defines the field of use |
| Sampling interval | adjustable from seconds to hours | balance resolution against memory and battery |
| Memory capacity | thousands to millions of readings | sets the runtime before readout |
| Battery life | months to several years | determines maintenance effort |
| Readout | USB, display, wireless or cloud | sets the effort of record keeping |
| Accuracy and calibration | e.g. ±0.5 °C, ±3 % rH, with certificate | secures the traceability of values |
A short interval and many quantities increase memory demand and power draw, so a compromise is needed. For regulated areas calibration also counts: a factory or accredited certificate proves that the displayed values lie within tolerance and hold up in an audit or dispute.
Where are data loggers used and how are they read out?
Data loggers secure records wherever climate has to be proven over time. Readout ranges from a manual USB download through reading the display to automatic wireless or cloud transfer, where values and alarms are available without an on-site visit.
Gap-free temperature records for food, pharma and medical goods as proof of compliance.
Monitoring temperature and humidity in the warehouse and the ESD protected area to safeguard components.
A logger travelling in the container or truck documents climate and shock in transit.
Archived time series serve as a test log for audits, complaints and certifications.
Alarm thresholds turn the logger into an early-warning system: if an upper or lower limit is exceeded, the device signals it via display, LED, buzzer or - on networked models - by email and push notification. This allows a response before goods are damaged. For reliable evidence, loggers should be calibrated regularly and the results documented with date and inspector.
Frequently asked questions
How often should a data logger measure?
The interval depends on the application: for a stable storage climate 10 to 30 minutes is often enough, while cold chain or transport use shorter gaps of 1 to 5 minutes. Shorter intervals give more detail but fill memory and drain the battery faster.
How is the data read out of the logger?
Depending on the model via a USB connection to a PC, directly on the display, over a wireless link or automatically to a cloud. Networked loggers provide values and alarms continuously without anyone having to be on site.
Does a data logger need calibration?
For documentation-bound areas such as pharma or food, yes. A factory or accredited certificate proves the accuracy, and regular recalibration ensures the recorded values stay within tolerance and count as evidence.
Find the right data logger
From a simple USB logger to a networked system with cloud and alarms - we help with measured quantities, accuracy and climate monitoring.
Neutral advice
Recommendation by application and accuracy, independent of brand.
Combined units
Loggers capture temperature and humidity in one continuous time series.
ESD focus
Climate monitoring as a building block of a stable ESD control concept.
Related reading
More at /en/ratgeber/temperature-measurement and /en/ratgeber/humidity-measurement.