If you’ve ever wondered if using the revolving door really makes a difference in conserving energy, Slate’s Green Lantern has an answer for you. It does! The reason is similar to why hot air rises - it creates higher pressure than cold air (if any of you science types want to correct my wording, please do). So when someone opens a door when it’s hot out, the hot air gets sucked in by the lower pressure created by the cold air inside.
Now for the environmental findings: in the building tested by an MIT team of grad students, use of the revolving door would have reduced carbon emissions by 14.6 tons, the equivalent of taking more than 2 cars off of the road, and would have saved 75,000 kilowatt-hours of energy.
