U.S. President Barack Obama has pledged to put 40 million of the so-called "smart meters" into American homes as part of the economic stimulus package but in some European homes the devices are already a reality and helping users to save month.

At the Cebit IT fair in Hanover last week, German utility Energie Baden-Württemberg (EnBW) was demonstrating its smart meter, which has been available to customers since late 2008.

The meter is available to homes for €5 per month (US$6.34) but customers who use its many reporting features can typically save more than that amount in electricity usage, said Jörn Kröpelin, from the company's strategic product department.

The meter itself has a simple LCD showing current consumption so subscribers need a PC to take advantage of its benefits.

There are two interfaces available. One Web-based interface provides reports down to 15-minute intervals via EnBW's server and includes historical data as well so users can, for example, compare current usage to that of their house the same time last month or last year or, via a recently added function, to that of an average home.