Glossary of terms

The emissivity of an object depends on the material and the structure of its surface. This specifies how much infrared thermal radiation the object emits compared with an ideal radiant warmer (black body, emissivity ε = 1) and accordingly has a value between 0 and 1.

A thermal bridge is defined as a position on the external wall of a building, where there is a localised increase in heat loss due to a structural defect.

Thermal bridges can lead to an increased risk of mould.

The relative humidity indicates the degree to which the air is saturated with water vapour. The value is indicated as a percentage of the maximum amount of water vapour the air can absorb. The maximum amount of water vapour depends on the temperature: The higher the temperature is, the more water vapour the air can absorb.

If the relative humidity is too high, there is an increased risk of mould. If the relative humidity is too low, it may have a negative impact on your health.

The dew point temperature indicates the point at which the water vapour in the air starts to condense. The dew point temperature depends on the relative humidity and the air temperature.

If the temperature of a surface is below the dew point temperature, water will start to condense on this surface.

Condensate on surfaces is one of the main reasons why mould forms.