Temperature Sensors and Data Logging — PRN Equipment Guide

## Why temperature matters in investigation Temperature anomalies are among the most commonly reported environmental features of reportedly haunted locations: localised cold spots, sudden temperature drops, or unusual thermal gradients that appear to move through a space. Documenting these rigorously requires the right sensors, correctly deployed, with honest evaluation of mundane explanations. ## Sensor types **Thermistor-based sensors** are common in handheld consumer devices. They are inexpensive, reasonably accurate (typically ±0.5–1°C), and measure air temperature at a single point. They respond with a time lag — the sensor must reach thermal equilibrium with the surrounding air, which can take several seconds to a couple of minutes depending on mass and airflow. **Type K thermocouple sensors** respond faster and can cover a wider temperature range, but require a signal conditioning board and are more often found in professional data loggers than consumer paranormal devices. **Non-contact IR thermometers** measure surface temperature via a spot of emitted infrared, not air temperature. The readings vary with the target surface's emissivity (see the thermal camera guide). They are useful for quick comparative sweeps but poor for documenting air temperature anomalies. ## The data logging advantage A single handheld temperature reading is nearly meaningless. A time series — temperature logged at regular intervals (e.g., every 10–30 seconds) over the entire investigation period — shows you the pattern: does a temperature anomaly coincide with a specific time, an investigator's position, or a building system cycle? Multi-point logging (several sensors deployed simultaneously in the same room and adjacent rooms) lets you distinguish a localised anomaly from building-wide environmental drift. If the temperature drops in every room at 01:15, that is probably an HVAC system shutting off. If only one room drops while others hold steady, that is a more interesting finding. ## What to log alongside temperature For temperature data to be meaningful, you need concurrent logs of: - Investigator positions (or absence from the room) - Doors and windows open/closed state - HVAC/heating system status - Any equipment running that generates heat - Outdoor temperature if known (weather station or public meteorological data) Without this environmental context, a temperature fluctuation cannot be meaningfully evaluated. ## Selecting a data logger - Look for **timestamped CSV or text output** that you can import into a spreadsheet or analysis tool. - Check the **stated accuracy and resolution** — consumer devices claiming ±0.1°C are often optimistic; treat ±0.5°C as a realistic working figure. - Consider **battery life**: a sensor that switches off mid-investigation creates a data gap that can look like an anomaly. - Multi-sensor units that log temperature, relative humidity, and barometric pressure simultaneously are valuable — relative humidity affects perceived temperature and can indicate airflow paths.