For most drivers, the rear defroster button is an afterthought. You jab it on cold mornings, watch the frost melt into streaky rivulets, and then forget about it until the next weather event.

It's hard enough to wake up on a cold morning and head to work. It's even worse when you look at your windshield and it's frosted over. Sure, there's the temptation to scrape off enough to see and ...