The world's first large-scale test of new technology that uses the heat produced by computers to warm buildings is about to begin in Switzerland.

The hope is that the three-year trial of the system, called Aquasar, will lead to carbon emissions reductions of 85% through simultaneously cutting the energy used to cool the chips while also reducing heating bills.

Long-term, the main target for the technology is not desk-top computers in homes and offices but the growing number of data centres that form the backbone of the internet and keep businesses ticking over, according to Bruno Michel, who is heading the project at IBM's Zurich Research Laboratory, in Switzerland.

Precisely how much energy existing data centres consume is not clear, largely because companies like Google are reluctant to reveal just how many they have and how big they are. But according to Tom Dowdall co-ordinator of Greenpeace International's Green Electronics campaign they are consuming increasing amounts of energy. "Data centres are one of the main reasons why electricity use is rising in Europe and the US."

In 2005 data centres were responsible for 1% of global electricity consumption, double the figure of five years earlier, according to Jonathan Koomey, an energy expert at Lawrence Berkeley National Laboratories, in California. And soaring internet traffic means this figure is set to rise rapidly.

Around half of the energy consumed by large computer systems is spent cooling the processors to prevent them from overheating – normally by blowing refrigerated air over them. In contrast the Aquasar system uses water to cool the chips, which is 4000 times more efficient at capturing heat.

IBM's new system uses a network of tiny tubes measuring just hundredths of a millimetre across to pump water to within a few hundreds of a millimetre of the chip itself. In the three-year pilot study, this heated water will be used to warm a separate water system to about 65C. This hot water will then be plumbed into the district heating system that serves 60 buildings in the Swiss Federal Institute of Technology, in Zurich.

The drive for change, according to Dowdall, is coming not from a desire to reduce emissions but from the escalating electricity bills data centres are generating. "Companies can't keep increasing their capacity with the current costs," he said.

Google is already working on other strategies to reduce its power bill. One idea is to place data centres on barges and use sea water to cool them. Another suggestion is to make use of cooler temperatures undergound by placing data centres within old coal mines.