Self cleaning double glazing 

Double glazing that needs little cleaning may well mean soap and chamois are a thing of the past.
What is self cleaning double glazing glass? Self cleaning glass for double glazing is a special glass manufactured by Pilkington which allows organic dirt to be washed off the double glazing glass every time it rains or is hosed down, and is ideal for double glazed windows and conservatories
Self-cleaning double glazing is an ordinary float glass with a special photo catalytic coating. It is made by chemically bonding and integrating a microscopically-thin surface layer to the exterior surface of clear glass of the double glazing. The integrated coating reacts to the sun's ultraviolet rays to gradually and continuously break down organic dirt through what is called a photo catalytic effect. In other words photo catalytic means that the active integrated coating on the outside of the double glazing absorbs the sun's ultraviolet rays. This causes a reaction on the surface which breaks down dirt and loosens it from the glass. This type of glass also has hydrophilic properties, meaning that rain flows down the pane as a sheet, washing away the dirt instead of, as with normal glasses, leaving the dirt behind. As a result of these two effects, the special self-cleaning coating keeps the glass cleaner for a longer period than with normal glass in applications where it is exposed to the rain.

Natural breakdown
The environmentally friendly improvement is a result of a lengthy process of research and development, begun in the early 1990s, into "thin film" technologies.
"It took five to seven years from lab to the production line."
"Each time harsh chemicals are used, they are washed off into ground, which produces contamination. What we say here is that you can just spray water on top."
There is an additional safety benefit too.

Normal glass (left) and Activ (right) makes for clear views Each year people are killed and hurt using ladders to clean windows. This should now reduce because you can use a hose pipe to reach the first floor windows."