Trouble is, it doesn't always work. The cases use extra energy to cool the air that leaks in. So researchers tested the ubiquitous cases. They shot air across the front to try out a variety of speeds, angles and other factors. They used a tracer gas to measure warm air infiltration.

 

And they found that the key players are the angle of the air grills and what's called a Reynolds number—which involves the air jet's speed and density and the jet's turbulence.

 

By adjusting these variables, they were able to get a ten percent reduction in warm air infiltration. Which the researchers say could save $100 million worth of electricity each year. The research was published in the journal Applied Thermal Engineering. 

 

The researchers have designed a system so that fridge case manufacturers can optimize their companies' designs. And save us all some cold cash.

 

Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.