With its long-term stable humidity sensor, the testo 175 H1 is the professional data logger for the monitoring of temperature and relative humidity in work and storage rooms. The external probe (stump) stands out thanks to faster reaction times in comparison to probes installed inside the housing. Energy savings are an important topic for buildings. However, better external insulation and new, energy-efficient windows can also have undesired side-effects. With the targeted reduction of "natural" ventilation, more heat is retained in the building on the one hand, but on the other hand also more humidity, caused, for example, by the inhabitants. In badly ventilated places there is therefore the danger of mould growth. The testo 175 H1 continuously records temperature and humidity values and shows the dewpoint in the display. The indoor climate is thus monitored, emphasizing the need for targeted ventilation and air exchange.