Dehumidifier runs but collects hardly any water – what's wrong?

If a dehumidifier collects very little water, the most common reasons are that the room temperature is too low (most units only work efficiently above around 15–18 °C), the filter is dirty, or the water tank isn't seated correctly and the float switch is stopping the unit prematurely. Remove the filter and rinse it under clean water, or replace it according to the manufacturer's instructions. Empty the tank completely, dry it, reinsert it fully, and make sure it sits correctly. Position the unit as centrally in the room as possible, not right up against a wall. If ice forms on the cooling fins, the room is too cold or the unit is faulty – in either case, switch it off and let it defrost. If performance remains poor, the refrigerant may be depleted: contact a qualified technician.