I try to do my best to charge the same as I did for traditional window cleaning, the danger is that you will end out dropping your prices because you are that much quicker.
If you are crafty I guess you could use the fact that you are using the latest expensive gear, to bump up your prices, useful if you have existing accounts that are underpriced.
Just keep your price structure the same and you will be ok, and you will definitely make more money than you were doing so before
Ian