Cold Spots Explained: What Causes Them and How to Actually Detect One

"Cold spot" is one of the oldest reports in the field, and one of the easiest to get wrong with the wrong tool. A handheld thermometer can tell you one point is cold. It can't tell you the shape of the cool area, whether it has a defined edge, or whether it's just a draft from the door you didn't notice. Here's the difference between chasing a cold spot by hand and actually imaging one.

1.0What a Cold Spot Report Actually Means

A cold spot is a localized area that reads noticeably colder than the space around it, with no obvious source like an open window, a vent, or a draft under a door. The key word is localized: a whole room being cold isn't a cold spot, it's just a cold room. What makes a reading worth investigating is a defined, bounded area of temperature drop that doesn't line up with an ordinary airflow source.

2.0Why a Pocket Thermometer Falls Short

A handheld infrared thermometer reads exactly one point, wherever you aim it, one reading at a time. That's enough to confirm a spot is cold, but not enough to see its shape, its edges, or whether it's actually a thin stream of air moving across the room from a door or vent you didn't clock. Sweeping a handheld unit point by point across a wall is slow, and by the time you've covered the area, whatever caused the reading may have already moved or dissipated.

What it can't do: show a whole scene at once, capture a shape or a moving boundary, or log the reading anywhere beyond whatever number you wrote down.

3.0What a Thermal Camera Sees Instead

A thermal imaging camera images an entire scene as a temperature map, all at once, in real time. A localized cool region shows up immediately as a visibly distinct shape against the rest of the frame, so you can see its edges, whether it's moving, and whether it traces back to a vent, window, or doorway before treating it as anything unusual. That's the difference between a single number and an actual picture of what's happening across the space.

4.0Turning a Thermal Feed Into Logged Evidence

SPECTER can bring a thermal camera feed in over RTSP and run live anomaly detection on it, including a dedicated Cold Spot detection type built specifically for a localized low-temperature region in the thermal frame. When one fires, it isn't a number you have to write down, it's captured automatically.

• Automatic capture on a hit. A confirmed cold spot detection saves a snapshot the instant it crosses threshold, no one has to be watching the feed at that exact second.
• Global timecode. Every capture is timestamped against the same project clock as your other cameras and sensors, so you can check what else was happening in the room at that moment.
• Filed in your evidence archive. Every hit is saved with type, class, confidence, and timecode alongside everything else from the session, not scattered across notes.

5.0Thermometer vs Thermal Camera, Side by Side

6.0Getting Started

If you already run a thermal camera, connect it over RTSP and let SPECTER watch it for you instead of sweeping the room by hand. If you don't have one yet, the rest of SPECTER's detection still runs on RGB and depth alone.

7.0Frequently Asked Questions