A dehumidifier does 3 things: it draws in moisture from the air, collects this moisture into a water tank, and releases purified air back into the room. This helps to maintain a healthy humidity level of 40% – 50%. Additionally, a Dehumidifier can dry clothes on a horse with Laundry Mode switched on. Some models can also purify the air around you using filters to create a comfortable and safe environment. Even in well ventilated areas, a dehumidifier can eliminate moisture build up, for instance in the bathroom caused by hot running water, in the kitchen from a boiling kettle and saucepans, or perhaps in the conservatory from drying laundry and indoor plants.
A Compressor Dehumidifier works like a little fridge. It draws in the air from the room which passes through a filter and then over cold coils (much like those on a refrigerator). As the coils cool the water condenses and drips into the water bucket within the unit, the air is then reheated to room temperature and blown back out of the dehumidifier. A Compressor Dehumidifier work best above 20°c. They are less effective in cool conditions.
Whilst compressor dehumidifiers only work really well in warmer temperatures, desiccant units extract the same amount of moisture in any temperature between 1°c and 20°c. Desiccant dehumidifiers use a desiccant material, like Zeolite, which absorbs water vapour from the air in a similar way to silica gel. The moisture is then extracted from the desiccant by heating.