Is indoor air drier than in the Sahara?
This can lead to production problems.

Published 2022-12-12

In winter, indoor air often becomes dry. This can cause physical discomfort for people and lead to static electricity that disrupts production processes. To detect and overcome dry air, it is useful to measure, and preferably log, air temperature and humidity over a longer period.

Cold air can hold less moisture than warm air. Therefore, the air becomes drier in winter. And when we bring in this cold air and heat it, the indoor air becomes dry. This low humidity can cause discomfort in the form of dry skin, irritated airways and eyes, fatigue and headaches.

Static electricity – an annoying saboteur

Dry indoor air can also result in static electricity, which occurs at the surface of materials when there is either a deficit or excess of electrons. We can then experience unexpected and unpleasant shocks. The voltage can be high but the current is very low. Therefore, these shocks are often harmless to us. However, there is a risk of equipment and processes being affected.

Electronics and printed circuit boards are sensitive to static electricity. In addition, static charge attracts dust and other unwanted particles, which can have a negative impact on production processes. Lower production rates, sudden and costly downtime, the need for extra maintenance and, in the worst case, replacement of parts are examples of some common failures. Disruptions in production can also ultimately lead to lower product quality.

Moisture – an important measurement parameter

This diagram shows how people and materials are affected by ambient humidity.

For us humans, it is about avoiding ill health. For materials, this may involve avoiding disruptions in manufacturing processes or storing in a climate that provides the best durability.

Humidity levels can fluctuate rapidly, a 10°C drop in outdoor temperature can reduce indoor humidity by almost 15%RH. Measurement provides knowledge of the situation and the ability to influence it.

Cold outside means dry inside

The table shows what happens when humid outdoor air is brought in and heated to 22°C. For example when outdoor air with 80 % humidity and a temperature of -5 °C enters and is heated to +22 °C, the relative humidity drops dramatically to only 14 %RH. An average humidity in the Sahara is around 25 %RH!

Data loggers that give you control of the dry air.