We just installed the sun shades purchased when we took delivery on the 2008 PC 2551 in June. Wow what a difference they make in heat transfer through the windshield and side glasses! Had the PC sitting in the driveway facing East with the late morning sun bearing down right through the windshield. (Did not plan it that way, just the way my driveway is located.) After my son and I got the side glass shades on, we laid out the windshield screen so we could position the inside magnets properly for installation. I could tell right away that there was very little heat transfer. After finishing the installation of the magnets we left the shades on for a couple of hours and I was amazed at how much the shades reduce the heat inside the cab area. That means the roof AC unit can cool the rest of the coach better. If you don't have a set of these new sun shades, I would heartily recommend you make the investment.