Sky says it is to help customers reduce their household energy bills with the introduction of a new feature that will automatically switch inactive Sky HD and Sky+ boxes into standby mode overnight.

The ‘Auto Standby’ feature will be introduced to more than two million customers’ boxes in phases over the next few months.

It will be 'sent' automatically to all Sky HD boxes from tomorrow. Sky+ boxes manufactured after August 2005 will receive the update between 18 and 24 April 2007. All other Sky+ boxes will receive Auto Standby later this summer. Sky is also exploring the potential to deliver Auto Standby to standard Sky boxes.

Ben Stimson, Sky's director of corporate responsibility, said: "Energy use is a growing priority for companies and consumers alike so we want to help our customers to cut their bills and reduce their environmental impact. We advise all our customers to switch their Sky box to standby when not in use. But for those occasions when people forget, Auto Standby will be there to help out. This is a UK first whose effects will add up to a significant reduction in energy consumption for our customers."

The new feature monitors whether people are using their Sky+ or Sky HD box overnight between 11.00pm and 4.00am. If the box has not been used for a period of two hours after 11.00pm, an ‘Auto Standby’ warning will pop up on screen for three minutes. If there is no further use the box will go into standby mode automatically.

Robin Oakley, senior climate and energy campaigner at Greenpeace, said: "Sky is among the few companies forging ahead to cut out energy wastage in their products, it’s time this became the priority for companies producing all our appliances."

This new enhancement forms part of Sky’s plans for ensuring its products are as energy efficient as possible. Since the launch of Sky Digital, Sky says the energy consumption of Sky’s new standard boxes has been reduced by 50%.