I have a Sunshade for the windshield from the shop here. Now it has lost the ability to remain rigid (vertically, sort of) after putting it on the windshield and securing the top with the visors. It sags to the point that it falls off its moorings and lets lots of heat in. I'm thinking of gluing some vertical plastic stiffeners on the inside (white side) to cure it, since I could still roll it up in the orthogonal direction to store longer-term. Before I go there, I request PriusChat wisdom on this subject.
Duct-tape!Not sure which one you have? A good replacement is the auto-shade Magic Shade! I got the Jumbo size at Target.Folds down to 1/10th its size for EZ stowage! Seems to work well.
Did you try writing the manufacturer and explain to them what is happening? Maybe it is uncommon or something and they will send you a replacement: Custom Windshield HeatShield for the 2010-11 Toyota Prius They have a 2 year warranty and you have to provide them with proof of purchase
The one I have from the Toyota dealer is made by Custom Auto Shade and has a lifetime warranty. $30 and a perfect fit. If you, or anyone else FTM, gets a new one I definitely recommend it.