We installed Hardi Artisan Plank on our house in '13, in Sailcloth color, a light yellowish. It got sufficiently dirty that I couldn't stand it any longer. I have a pw, but was reluctant to do the siding. I have been looking for a good telescoping brush with the hose attachment. I found an Ettore Car/Truck aluminum wand with a toggle water flow control and I went at it. I could control the flow on the wash and scrub portion and then spray it down with higher flow. It took a few minutes to figure out the orientation of the flow control and brush head. It was great and worked really well. The siding looks like new. I will likely do an annual PW in the future, but it was so bad in spots that it took a good scrubbing first. The hose sprung a leak just above the toggle control but the brush and wand are still good and I will adapt a valve to it with minimum fuss. For the $25 or 30 bucks, good buy! Oh, and I made sure not to extend the telescoping want to the limits. Maybe it will be okay, but I didn't want to chance it. I could get up to 8-9' off the ground.