The BL Compact TF-IR unit has sensors for surface temperature infrared measurements as well as for measuring air temperature, and air relative humidity. This combination of the different measuring techniques enables the TF-IR unit to be used for quickly and reliably assessing dew point undershoots or determining borderline conditions on surfaces such as walls, ceilings, floors as well as on window or door lintels. In addition to displaying the measured value, the unit creates an audible signal when a critical surface temperature is detected. When using the unit in due time mould formation (fungal growth) may be prevented and occurrence of moistening caused by condensation may be assessed reliably. Produced by Gann, distributed by Volta.