The secret of Pilkington Activ™ self-cleaning glass lies in its special coating, which works to keep your windows clean in two stages:

First
Using a "photocatalytic" process, the Activ™ glass coating reacts with ultra-violet rays from the natural daylight to break down and disintegrate organic dirt...

Second
Rain water washes the glass clean! Because Activ™ glass is "hydrophilic" water spreads evenly over the surface, instead of beading or forming droplets. As it runs off, it carries the dirt away with it. Activ™ glass also dries off very quickly, so it does not leave unsightly drying spots. And if you experience a dry spell, running a garden house on windows with Activ™ glass does the job too!