The US Government has announced new energy efficiency standards for external power supplies used in electronics such as mobile phones and laptops.

They are expected to help consumers save nearly $4 billion on their energy bills and cut carbon pollution by 47 million metric tons over the next 30 years, according to the US Department of Energy.

The new standards call for external power supplies to be made 33% more efficient. More than 300 million external power supplies are shipped in the US every year, with the average American home having five to 10 of them.

Energy Secretary Ernest Moniz said: “Appliance efficiency standards and high quality appliances go hand-in-hand, and represent a huge opportunity to help families and businesses save money by saving energy.”

The US Government recently also set new efficiency standards for lighting fixtures used in warehouses and parking lots.