We had our Designer done two weeks ago and had a fantastic job done by Egner's. They use "low pressure" which is what I wanted. He explained it this way, low pressure but has a larger quanity of water. Charged me $52.00 for the house, $10.00 for the Lanai and $25.00 for some stubborn spots where the roof bled on the siding. He had to get some strong soap and a brush to scrub it by hand.
Will I use them again, you bet I will.