The minerals (salts, ions) are removed from tap water by means of an ion exchange unit. Since the absence of salts and water hardeners means that less scale forms on the cleaned surfaces, this water is preferred for glass and façade cleaning. The water is demineralised by means of a cartridge, which obviously needs to be replaced from time to time and is thus a cost factor. The exchange cycle depends on the water hardness and consumption and the cartridges cost around €200 each. Apart from the fact that the manufacture and packaging of the cartridges uses additional energy, the treated water is not ultimately more effective than normal tap water. The type of improvement in cleaning performance that is achieved through the systematic addition of cleansing agents cannot therefore be expected from demineralised water.
