WFP work is a nice add on for pressure washing a home. You can easily sell the full exterior and tack on a couple hundred. It works out to run about $100 to $150 an hour for exterior only. What hurts time is often screens and interior cleaning. We are primarily a window cleaning company so it has been a great tool for us both on homes and commercial multi story properties. There really isn't any reason a pressure washer guy can't make decent money doing windows. We find it works best running single man crews when doing homes and pw.