Saab introduced the cooled seat a decade ago, and today it’s a common—but expensive—option in luxury cars (Saab’s “sport-ventilated seats” are $995 extra). A cheaper, do-it-yourself option is the Cold Seat ($49.95; coldseat.com), a quilt-covered gel-pack that sits over your kid’s car seat while you’re out of the car. Remove it, and the seat and buckle are cool, not hot.

The Chrysler Sebring and the Dodge Avenger feature cup holders that keep cold drinks at 35 degrees and hot drinks at 140 degrees ($795 to $1,295 including other options). Then there are air-conditioned glove boxes, available in the VW Jetta, for one, and cooled center consoles, found in some models of Lexus and Range Rover. Remote-start cars, like the Chevy Tahoe, allow you to turn on the car and the air conditioning before you hop in. How cool is that?