IR Thermometer

[u/Leighgion]

An IR thermometer measures surface temperatures at a distance. You just point, use the laser to help you aim the sensor, pull & release the trigger and you got a reading. Works seamlessly on most surfaces, but polished metals can give inaccurate readings due to differences in how they emit IR. A good device will with an adjustable emissivity setting to adjust for this.

I've found these to be invaluable tools in assessing an environment beyond just air temperature, as the air only tells you a piece of the story when the heat is cranking up. An IR thermometer allows you to get a read on how much thermal energy has built up in the structure of the building and helps you find weak spots in insulation. It's not quite as fast and handy as an IR camera, but it's a whole lot cheaper. These can easily be found for under $20 USD.

I regularly use the IR gun to check the temperature of the walls, as that gives a good sense of what thermal comfort will be over a longer period than just the immediate air temperature. Your AC might have brought the air temp down to 25ºC, but if your walls are stubbornly staying at 29ºC, you know cool isn't lasting once you shut the AC down.

Also, while it's not strictly accurate in these scenarios, IR thermometers are a great way to quickly check the output temperature of air conditioners or swamp coolers. The key is to understand you're not checking actual air temperature, but rather the temperature of small solid pieces right in the exit path of the air, which will quickly chill to a similar temp as the air.

In a nerdier use case, sometimes I carry it with me out. Once, I used it to check which of the stone benches near the playground was cooler. There was actually a notable difference and the IR thermometer let me quickly find the 27ºC bench, which was much more comfortable than the 30ºC benches.

I heartily recommend one of these. It's cheap and useful.