I have one of the Flir dongles (bought for work: I work with high-power LEDs) and I've gotten quite obsessive about looking for draughts and insulation gaps. It

I have one of the Flir dongles (bought for work: I work with high-power LEDs) and I've gotten quite obsessive about looking for draughts and insulation gaps. It gives you spot temperatures on the screen too, which is really useful. Seeing the icy-blue draught pouring through the broken cat flap seal and pooling on the floor was a wake-up call.