Which machine for which job
In a heated home, a compressor dehumidifier handles condensation and indoor washing on a few hundred watts, while a desiccant model keeps working in a cold garage, loft or boat. Drying out after a flood or a new screed takes commercial dehumidifiers, with air movers lifting moisture off floors and walls so the dehumidifier can pull it from the air. Indoor pools and hot tubs need a machine built to run all day in warm, chlorinated air.
Reading the litres a day figure
Dehumidifiers are compared in litres of water a day, with compressor models usually tested at a warm, wet 30°C and 80% relative humidity (RH), so expect around half that in a heated room. Desiccant models are usually rated at a cooler 20°C and 60% RH, so their smaller figures go further. As a rough guide, homes need 10 to 25 litres, flood and building drying 40 to 90 litres a machine, and pool rooms are sized to the water.
Power, drainage and the humidistat
Home machines plug into an ordinary socket, building sites usually run 110 volt kit through a transformer, and large fixed units need a qualified electrician. Water goes into a tank you empty, a hose to a drain below the machine, or a pump that lifts it to a sink. A humidistat set to around 50 to 55% in a home, or 60% in a pool room, keeps running costs down, and a clean dust filter keeps the air moving.
