Dehumidifiers

A compressor dehumidifier is similar to a small refrigerator in how it operates. The dehumidifier draws air from the room, filters it, and then passes it through cool coils (much like those on a refrigerator). The air is then reheated to room temperature and blown back out of the dehumidifier. As the coils cool and the water condenses and drips into the water reservoir.
Optimal operation temperatures range from 5 °C to 30 °C. For the best results best to operate above 20 °C. This type of dehumidifier function great in hot weather but are less effective in cold weather.
In a regular household atmosphere, a 20-litre compressor unit can extract up to 5 litres under ideal conditions.

Desiccant dehumidifiers use a desiccant material. Usually, Zeolite, to absorb water vapour from the air. This functions in the same way that silica gel does. The air is drawn into the dehumidifier by a fan. This air is then passed through a rotating wheel that contains desiccant, which dries the air. The moisture in the desiccant is extracted by heating a section of the wheel that isn't being used to dry the air. All desiccant units are tested at 60% humidity (80% for compressor units) and 30 °C.
Regardless of the temperature at which the dehumidifier is operating, it extracts the same amount of moisture. A desiccant unit has no consumables. The desiccant material does not expire and does not need to be refilled or topped up.
A desiccant unit's lifespan will typically be longer than a compressor unit's. Due to its simpler operation with significantly fewer moving parts. No compressor, and no refrigerator gas stored under high pressure to fail.

Peltier dehumidifiers work by drawing wet air over a cold heat sink's front. The air condenses as it travels over the chilly surface. The water from the condensed air drips into the water tank, and the dry air is re-circulated into the room.