As someone who used to do housecleaning back in the day, I would encourage you to tip well if you are happy with the service. Although you are paying more for "green service" (which I applaud you for!) you can be assured that the people that are actually cleaning your house are not getting rich. I too, consider myself a generous tipper if the service is good, and if I go out to an expensive restaurant, I still give 20%+ if the service was good, even if the total tip seems kinda high-- I just factor it in. I also tip the maids at hotels. I feel like we tip everyone else-- waiters, taxi drivers, hairstylists, etc., why shouldn't we tip the people that do the dirty work and clean our rooms/houses, esp. if they do a nice job? People in this line of work (usu. women) make a lot less than most professions, and while a tip is not going to balance the monetary scales, it will show your appreciation, which is huge, esp. when she is scrubbing your toilet week after week! :)