IR thermometers operate on the principle that all objects emit invisible, infrared energy. IR thermometers measure the infrared energy emitted from the object in the eight to 16 micrometer region of the electromagnetic spectrum.
As energy moves through the atmosphere into the thermometer, it is read as it passes through the instrument’s optical system. There it is converted to an electrical signal. The signal is then displayed as a temperature reading.
A number of companies make IR thermometers, including Bacharach, Raytek, Exergen and UEi. When selecting an IR thermometer, examine the model’s performance in areas such as:
- Target size to distance ratio. Determine how far you and your thermometer will be from the target object. The farther away you will when using the thermometer, the higher the ratio needs to be.
- Emissivity. Emissivity refers to the amount of readable energy released by the object to be measured. Some IR thermometers have fixed emissivity levels, while others are adjustable. If you will be using your thermometer to measure objects with different emissivity levels, chose an IR thermometer with adjustable emissivity.