It is easily cleaned during dry spells by simply hosing down with water
What happens if you live in a hardwater area.
Hosing down won't do it the windows will end up with spots everywhere.
I have a couple of customers with pilkingtons self cleaning glass and i must admit they do seem to stay a bit cleaner but they still need cleaning.
One thing the tops of the windows do not get cleaned by the rain because of the overhang of the roof.
Self cleaning glass has been around a long time now and people have not rushed out to buy it and i dare say in 30 years time there be as many window cleaners as there is now.
Paul