FYI everybody - Rock Auto still has some closeout Solar Guards for
$3.75 plus shipping (I don't work there, I just buy a lot of closeout stuff there). If you buy like three or four they all come in one box and I think it saves on shipping.
They go on the outside of the windshield so the heat never makes it to the glass or the interior, and they block 100% of everything as far as I can tell. I use one on the Volt every day (in central Florida) and my dash is barely warm to the touch when I get in the car. Two or three other people at work also use them now. They can take a beating - I've had my Volt a year and a half, and I'm still using the same Solar Guard I used on Ron Burgundy before I had the Volt
Before I would try adding some permanent expensive film to your windshield I would try one of these. They only have the gold ones for SUVs but they have the gold, silver and blue ones left for cars
Here's the link :
https://www.rockauto.com/en/tools/ac...eld+cover,1247
UPDATE - since I was on their site I went ahead and bought three more - it was less than 20 bucks with shipping. I pretty much have a lifetime supply now!
I added a pic of how I put mine on every day. I shut the car off with the wipers up and hold the Solar Guard down with them since it gets windy here.