The dew point is the temperature to which air must be cooled to become saturated with water vapour. When further cooled, the airborne water vapour will condense to form liquid water (dew). Water vapour will only condense onto a surface when that surface is cooler than the dew point temperature. For example, you will see this effect when water appears (condensation) on the outside of a glass containing an iced drink. What we want to avoid in the interiors of caravans and motorhomes is the appearance of water on metal, glass and plastic surfaces that can then accumulate, creating the damp conditions for rot and mildew to thrive. Working with some realistic values, if the relative humidity inside your caravan or motorhome is 62% and the interior temperature is 20°C the dew point will be calculated to be 12.5°C. To put it another way, for these particular values, if any surface becomes cooler than 12.5°C, the water vapour in the air will condense on that surface.

The Remon-RV device contains relative humidity, temperature and barometric air pressure sensors. We also find the local ambient (outdoor) temperature and relative humidity from the MetOffice. The ambient values give us a good idea of what is going on at the outside surface of your caravan or motorhome. Remember, what we want to avoid is any interior surface becoming cooler than the dew point.

So, Remon-RV periodically checks the interior conditions, compares them with the exterior values and determines whether the dew point might be reached on the internal surfaces, such as walls and windows – if this is the case, we notify the owner with a damp warning.