If you don't mind taking a bit more time (it doesn't really take long!), consider the BMW i3 cover. It covers the windshield, the top 1/2 of the car (handier if you have the sunroof), and the two front windows. It really only takes a minute or so to put in place. It makes a significant difference in the interior temperature and blocks most of the UV that might get in those windows that might help preserve the seats and dash. My estimate is that in full sun, it keeps the interior temperature down by as much as 25-30-degrees. And, because it reflects a lot of that IR, the panels don't get as hot so they don't radiate on you once you do get started again. An interior one helps, but the heat already made it in. A lot is reflected back, but the shield eventually becomes hot and radiates some of that into the car...better to keep it out in the first place!