the things people are saying are all very true, it is not a big investment for us as we already have the pressure washer (fully commercial 200bar - 3000psi) all i have bought is the long hose and end atachments that go up the drain. I have been out with a local company and seen how its done and how to charge. we have very strong marketing (marketing was my background before window cleaning) and a very large customer base. My staff do 90% of our window cleaning and so on, I tend to do all the one off window cleans and jet washing, this is a new serivce just for me to do, and the money is very good. so if we only get a few jobs thats fine.