Non Contact Vs Contact Temperature Measurement? Which Thermometer is Right For You?

One of the most common questions we get at Techris Systems Ireland is: "Do I need a contact (probe) thermometer or a non-contact infrared (IR) thermometer?"

The answer depends on your application, accuracy requirements, and industry regulations - especially in sectors like food safety, pharmaceuticals, engineering, and environmental monitoring. In this guide, we explain the key differences between contact and non-contact thermometers to help you make an informed choice.

What are contact thermometers/temperature sensors?

Contact thermometers measure temperature by making direct physical contact with the object or substance being measured. These are commonly referred to as probe thermometers.

Types of Contact Probes:

Penetration probes – Pointed tips for internal temperature readings (e.g. cooked food)

Immersion probes – For liquids such as water, oils, or chemicals

Air probes – For measuring ambient temperature in chilled, frozen, or oven environments

Surface probes – For flat surfaces where a pointed tip would be ineffective (e.g. hot plates, metal surfaces)

Common Sensor Technologies in Contact Thermometers:

Thermocouples - Widely used due to their broad temperature range, fast response, and cost-effectiveness

Thermistors - High accuracy sensors ideal for food safety applications; Thermistor style sensors are generally used when higher accuracy is required. They have a narrower measuring range but they are regarded as one of the more precise everyday temperature sensors, offering high accuracy measurements of +/- 0.4°C or better.

PT100 sensors (RTDs) - Offer even higher precision; commonly used in laboratory and industrial reference applications

Best Used For:

Measuring core/internal temperatures (e.g. meat, liquids)

High-accuracy applications in food production, pharma, and calibration labs

Situations where regulatory compliance (e.g. HACCP) is essential

What are non contact thermometers?

Non-contact thermometers, also known as infrared (IR) thermometers or laser thermometers, measure surface temperature without physically touching the object. They work by detecting infrared radiation emitted by all objects above absolute zero, converting this energy into a temperature reading.

Benefits of Non-Contact Temperature Measurement:

Fast readings – Instant response, ideal for quick temperature checks
Hygienic – No direct contact, reducing cross-contamination
Safe – Ideal for hot surfaces, moving parts, or live electrical equipment
Accessible – Useful for hard-to-reach or hazardous areas

Limitations:

Measures surface temperature only – Not suitable for core/internal temperature checks
Lower accuracy compared to probe thermometers
Affected by surface emissivity and ambient conditions

Best Used For:

Quick surface checks in food processing, HVAC, equipment maintenance
Situations where speed, hygiene, or safety is a priority

Which Thermometer Should You Choose?

In a practical sense, the main differences between contact and non-contact thermometers can be summarised as follows:

Accuracy: Generally probe thermometers are considerably more accurate than IR thermometers

Response Time: IR thermometers are faster responding than probe thermometers – almost instant

Measurement capability: IR thermometers will only measure surface temperature (not core) so not always suitable for some food applications.

Why Choose Techris Systems?

With over 35 years of experience in temperature measurement and instrument calibration, we provide expert advice and support tailored to your application.
Wide range of contact and non-contact thermometers
Free calibration certificates traceable to National Standards
Support for HACCP and ISO-compliant processes
Trusted by food processors, labs, and engineers across Ireland