Until recently, thermal imaging cameras were bulky items used by firefighters and search and rescue teams. However, modern electronics have revolutionized this sector of the market, and it’s now possible to turn your smartphone into a professional thermal imaging camera.

But why would you need a thermal imaging camera? Well, imagine a device you can put in your pocket to measure extreme temperatures from a distance. Thermal imaging cameras are invaluable for DIY projects, troubleshooting central heating systems or tracking where all your expensive energy is escaping from your home.

The latest thermal imaging camera comes from the affordable InfiRay P2 Pro. This tiny device is available with a USB-C or Apple Lightning connector, depending on your phone type. You do have to make a choice when you order, so it’s worth bearing in mind, especially now Apple is shifting from Lightning to USB-C

As well as the tiny camera attachment, the InfiRay P2 Pro also ships with a magnetic macro lens for getting up close to components on faulty circuit boards. A thermal imaging camera is ideal for showing which tiny parts – even 0.25mm resistors – are defective and overheating.

The InfiRay P2 Pro weighs just 9g, is made from magnesium, and is finished in space grey. The camera has a 25Hz refresh rate and can measure temperatures ranging from -20° to 550° Celsius. The refresh rate is better than some larger and more expensive models, which often produce juddery images with a refresh rate of 10Hz.

The compact size of the InfiRay P2 Pro means it’s small enough to take anywhere or leave in a toolbox when needed. A small carry bag is supplied with the camera, but it probably needs slightly more robust protection like a hard case.

As well as taking still images, the InfiRay P2 Pro can capture videos, which is helpful if an object runs hot or cold. There’s also a Professional mode that enables temperature measurements in real-time in specified areas. You can even set specific temperature ranges.

Setting up the InfiRay P2 Pro is a slick process. When I plugged the device into my Apple iPhone SE, it linked me to the InfiRay app on the Apple store. Once installed, the app takes you through the setup process. I’m no expert in thermal imaging, so I opted to use Easy Mode and it was up and running in no time.

The camera can display monochrome or color thermal images where the hottest areas are white and the coldest black. With the color version, temperatures vary from black to purple, red, orange and yellow, each showing temperature variations. It’s great fun going out into a street at night and seeing which neighbor hasn’t insulated their roof.

Another handy use for the InfiRay P2 Pro is to see if your central heating radiators are functioning efficiently or whether they need the hydrogen bleeding off. It’s easy to see if the heat is uniform across the radiator. From testing my heating, I moved on to measuring all objects. It’s surprising to see how warm everyday things like a smartphone can get, especially ones running iOS 17 and Instagram.

The InfiRay app is simple and elegant, with options for precisely placing a point in an image to measure temperatures. You can even set an alarm for minimum and maximum values, which makes it an ideal tool for keeping an eye on the thermal efficacy of a piece of equipment. There’s also a measuring scale available; you can draw lines and rectangles on the image to highlight problem areas. Even the display can be changed with up to 11 palettes for customizing the colors.

The app can save still images and videos to your smartphone’s image library. You can also embed a picture within a picture, adding a regular photo from the phone’s camera to orientate the scene with the thermal image. That’s a handy feature for writing home survey reports. This camera could be an ideal purchase for a home energy certifier.

Verdict: The InfiRay P2 Pro is a handy little gadget. As an impulse buy for testing your home’s insulation efficiency, it’s a slightly indulgent purchase, but for building surveyors and anyone who compiles home energy reports, it’s a bargain. Central heating and air-conditioning engineers will also find the InfiRay P2 Pro useful. My one observation is that I’d like to see an adaptor made for those of us who have an iPhone with a Lightning connector but might soon be upgrading to one with USB-C. If you need a thermal imaging camera, the InfiRay P2 Pro is hard to beat at this price.

Pricing & Availability: The InfiRay P2 Pro is available from Amazon and costs $299 / £299 / €299.

More info: xinfrared

Tech Specs:

• Thermal resolution: 256 x 192 (49,152 pixels).
• Thermal range: -20° to 550° Celsius (-4° to 1022° Fahrenheit.
• Refresh rate: 25Hz.
• Thermal sensitivity: <40mk.
• Field of view: 56˚ × 42.2˚
Accuracy: ±2°C or ±2%.
• Connectivity: Lightning or USB-C.
• Dimensions: 27 × 18 × 9.8mm.
• Weight: 9g.