The fastest way to defrost your windshield, according to science Published: Tags: Sleet covers a windshield on Dec. 28, 2015 in downtown Detroit. (Dave Klein/WDIV Local 4) It’s winter in Michigan -- which means you’re probably having to defog/defrost your windows pretty often. Mark Rober decided to figure out what is the fastest and most efficient way to get your windows cleared. His method is said to be twice as fast as using your normal defroster. The video above explains how he came to find this method. It's pretty simple: 1. Turn the heater on at full blast 2. Turn on the AC