Published:
Water in a wet carpet moves into the room air by evaporation. Air at a given temperature can carry only so much water vapour; once saturated, evaporation stops and the carpet dries no further. A heater raises that limit a little but does not remove water from the room. Opening a window in winter brings in cold air that is already humid.
Four steps
- Intake: the fan pulls humid air from between the carpets into the unit.
- Condensation: the air passes over the cold evaporator surface; water vapour turns into droplets and drains out through the hose.
- Reheating: the dried air warms up as it passes the hot condenser surface.
- Return: dry warm air is blown back between the carpets, picks up more moisture and the cycle repeats.
The cycle runs in a closed room. Each pass lowers the water carried by the room air and drying progresses from the carpet surface into the inner layers. An M400 removes 400 litres of water in 24 hours this way; an M800 removes 800.
Why automatic defrost matters
Because the evaporator is cold, it frosts over at low room temperatures, and a frosted surface removes no moisture. Automatic defrost thaws the surface at intervals so the unit keeps running through winter.