There are a lot of misconceptions and bad practice going on surrounding the use of infrared temperature guns. Being in the HVAC industry, we see a lot of misuse and thought a breakdown on how they work and how to best use them will help you get the best results.
The Distance and Accuracy
First of all the laser light that shines out is only a guide to point where you want to check temp, these devices actually work by picking up the thermal radiation which an object gives off. The closer you are to the object being checked, the more accurate it becomes, kind of like focusing a camera lens. Farther away = less accurate; closer = more accurate. Even when focused perfectly they are only so accurate as other objects also give off thermal radiation, which can effectively skew the reading. A normal unit has an accuracy range of +/- 2* Celsius or +/- 4* Fahrenheit.
The Purpose and How to Avoid False Readings
The purpose for these guns is to get a “ball park” reading e.g. Testing a ceiling hung unit heater for operation, checking space temp in walk in coolers etc… It will not give you an exact measurement. The number one misuse of these instruments is being used to check product temps and pointing them at labels or plastic wrappers or anything shinny, they will absolutely give false readings in this case! They best work by pointing them at dull surfaces such as a box or a matte surface.
Always remember they are intended for “ball park” measurements, if you require an exact temperature reading this tool will not suffice and you must use another form of measuring temp. If you have any questions for our team, feel free to engage in the comment section!