I have a new toy: the Lasergrip 1080 infrared thermometer. It can measure the temperature of anything you point it at, with incredible accuracy. This winter it’s teaching me all kinds of things about the temperatures of the walls, ceiling, windows and floors of my house.

The most interesting insight is the strong evidence it has provided of the effectiveness of the draught stoppers beneath my doors. Take a look at the two photos above, taken at 7:30 this morning. The floor next to the door with no draught stopper—I removed it before I went to bed for this experiment—is more than 3 degrees Celsius colder than the floor protected from the cold air blowing under the door. Three degrees is a big difference when looking at indoor comfort.

I put that draught stopper back on right away.