External Power Supplies: Energy Efficiency Requirements

External Power Supplies: Energy Efficiency Requirements

In the early 1990’s, the U.S. Environmental Protection Agency (EPA) started a voluntary program to promote energy efficiency and reduce pollution, which eventually became the Energy Star program. However, it was not until 2004 that the first mandatory regulations dictating average efficiency minimums and no-load power consumption for External Power Supplies (EPS) were put into place.

As different countries enacted stricter requirements and moved from voluntary to mandatory programs, the Energy Star program defined the International Efficiency Marking Protocol to minimise confusion between regions and their similar standards. The defined markings set minimum average efficiency and maximum no-load power consumption levels for EPS.The evolution of the various marking levels is detailed below:

  • Level I: Power supply does not meet any of the standards defined
  • Level II: Power supply meets minimum efficiencies that were set required by China in November 2005
  • Level III: Power supply meets Energy Star Tier 1, CEC Tier 1, and Australian MEPS standards
  • Level IV: Power supply meets EISA 2007, CEC Tier 2 and the Australian MEPS High Efficiency category
  • Level V: Power supply meets CEC Tier 3 and EU phase 2 standards
  • Level VI: Power supply meets DOE new standards, to go into effect in the US on February 10, 2016

Below are the countries or regions mandating that external power supplies (EPS) (with some exemptions) shipped across their borders meet specific efficiency levels:


  • IV – United States (current)
  • IV – Canada (current)
  • V – European Union (current)
  • VI – United States (2/10/16)


Article from a White Paper by SL Power