Launching for the first time in the UK today, Google Powermeter is an online tool that allows householders to monitor their home's energy use and greenhouse gas emissions via the web, and so reduce their consumption and save money.

Already being trialled in the US, the free energy-monitoring service uses new smart meters, or an add-on clip for conventional meters, to send electricity consumption to a personalised iGoogle web page. Users will be able to check their energy use anywhere in the world via a computer or mobile phone.

The idea is that householders will be persuaded to stop overfilling kettles, switch appliances off standby and turn off unused lights after being confronted with their daily energy use. Studies by organisations including the government's Energy Saving Trust have suggested such energy monitoring leads people to cut their bills by 3-15%, potentially saving the average UK household £75 a year.