How to choose a temperature and humidity meter
By Grant, Inspection Tool Specialists. Reviewed November 2026.
Three things decide which temperature and humidity instrument you need: what you measure (air temperature, surface or process temperature, humidity or dew point), whether you need a spot reading or a record over time, and whether the readings must be sent to someone else or into a report. Answer those and the choice narrows quickly.
This guide covers thermo-hygrometers, dew point meters, infrared and contact thermometers, and temperature and humidity data loggers.
Air, surface or process?
| What you need | Instrument type | Typical use |
|---|---|---|
| Air temperature and relative humidity, spot check | Thermo-hygrometer | Rooms, stores, workshops, HVAC checks |
| Dew point | Dew point meter | Checking the dew point before coating or painting work |
| Surface temperature, without contact | Infrared thermometer | Surfaces, machinery, food and process checks where you cannot touch the item |
| Temperature inside a material or liquid | Contact or probe thermometer | Process temperatures, food probes, core readings |
| Readings over time | Data logger | Storage and cold rooms, shipments, climate records |
Why dew point matters before coating
Coatings can fail when the surface is at or near the dew point, because moisture condenses on it as the work proceeds. Measure the air temperature, the humidity and the surface temperature together, then work out the dew point. A dew point meter gives it directly. The margin your coating specification requires between surface temperature and dew point sets the go or no-go decision, so check that figure before you start.
Infrared or contact?
An infrared thermometer reads a surface without touching it, which is quick and safe on hot or moving equipment. Its reading depends on the surface: shiny or reflective surfaces read low unless you adjust the emissivity setting. A contact or probe thermometer measures what the probe touches, so it suits liquids, food and the inside of materials. Choose contact when the reading must be the true temperature of the item, and infrared when speed and access matter more.
Logging and alerts
A single-channel logger records one location. A multi-channel logger records several probes on one unit, which suits cold rooms or a process with several points. WiFi and GSM loggers send readings and alarms to a phone or computer, so someone can act before a fault becomes a loss. Check how often the logger records, how long it stores data when the connection drops, and whether it supports the alarm limits your procedure sets.
Calibration
Check any instrument against a reference in the range you use, and keep the record. For records that a client or auditor will check, buy the instrument with a calibration certificate. Calibration certificates are available at extra cost on many models, so ask when you order.
If you need a particular brand
We don't carry every brand. If a specification names one, tell us the brand and model, and we will quote the closest equivalent from our range and say where it differs, such as range, accuracy or logging. That way you can decide whether it meets the requirement before you order.
Which instrument should I buy?
| Application | Suggested starting point |
|---|---|
| Quick room checks, tight budget | GM1372 digital thermo-hygrometer |
| Dew point checks before coating work | AH-192D dew point meter or PCE-THB 38 dew point meter |
| Surface temperature without contact | M320 infrared thermometer or PCE-IR 90 |
| Probe or contact readings | PCE-T 330 surface and probe thermometer |
| Logged temperature and humidity, remote alerts | S700 WiFi data logger or PCE-HT 420IoT |
| Several temperature points, thermocouple probes | S220 thermocouple data logger or PCE-T 1200 multi-channel logger |
As a guide to our current range, including VAT: thermo-hygrometers from about R520 to R4,640; dew point meters from about R5,080 to R7,350; infrared thermometers from about R980 to R7,120; data loggers from about R4,430 to R17,550. Prices change, so check the product pages and confirm whether you need a calibration certificate.
Questions we will ask you
Tell us what you measure (air, surface, process or inside a material), the temperature and humidity range, whether you need a spot reading or a record over time, how many points you monitor, whether readings must reach someone remotely, the alarm limits your procedure sets, and whether the readings must come with a calibration certificate. With that we can recommend an instrument and provide pricing.