In 2005, all the network-interface controllers in the United States (in computers, switches, and routers) used an estimated 5.3 terawatt-hours of electricity.[14] According to a researcher at the Lawrence Berkeley Laboratory, Energy Efficient Ethernet could save an estimated $450 million a year in energy costs in the U.S.[15] With most of the savings from home computers ($200 million), and offices ($170 million), and the remaining $80 million from data centers.[15] Energy efficient Ethernet saves energy by allowing network links to either go into a low power sleep mode or run at a slower rate when there is no data. It also defines lower power signaling for use on higher quality cables.