ive posted on this topic numerous times, i clean for one of the ex bosses of pilkington and now a major shareholder in pilkington, his house is all pilkington activ "self cleaning" glass, the stuff doesnt work......at all. infact it makes larger bits of dirt stick to it and become baked on. It actually makes the windows dirtier, yes that right, dirtier. Not with the usual type of soft film of dirt but it attracts horrible massive bits of dirt, and as i said they get baked on to the glass, terrible stuff. Oh and charge more to clean it, especially as a fist clean...alot more, this stuff takes ages the first time.