Cooling on Hot Days

The clay plaster of the naturbo interior insulation has a cooling effect on the room air. To describe the effect, we need to take a bit of a look at this point:

The relative humidity of the room air is expressed as a percentage. This is the ratio of humidity in the room air compared to the maximum possible humidity. This maximum humidity in turn depends on the temperature of the air. The following applies: the warmer the air, the more moisture it can hold.

Here is an example with a room with 21 °C air temperature and 50% humidity in the morning: this corresponds to a water vapour content of approx. 9 g/m³ air. In fine weather in summer, the room air warms up to 30 °C during the day. At this temperature, the room air could hold up to 30 g/m³ of water vapor. However, the existing 9 g/m³ now only correspond to a value of 30%. The humidity is therefore reduced by 20% due to air warming.

Clay plaster now has the unbeatable property of balancing the humidity in the room at 50%. As humidity drops, it therefore evaporates moisture into the room. Evaporation inevitably produces evaporative cold (the same effect that makes us sweat at too high temperatures), which in turn helps to cool the room.

And in this way, the clay plaster dampens the warming in the room on hot days.