A lot of energy innovations have a “back to the future” feel about them, in which new methods of using traditional mechanisms are leveraged to make simple changes that result in significant gains.

Data centers consume as much as 3% of often-strained US power generation, the vast majority of it in keeping the huge buildings where servers are stored cooled with air conditioning to prevent the servers from overheating.

The high-tech solution is a combination of software and smart servers that go into stand-by mode when they aren’t required.

The low-tech solution, highlighted in this video from the Department of Energy‘s Energy 101 series, is to use the heat from the servers funneled through heating ducts into offices and, in hot months, to circulate the air underground where it cools.