People in urban areas who want to save the planet would do better to use the washing machine at a lower temperature than buy a wind turbine, scientists said yesterday.

The experts praised David Cameron, the Conservative leader, for setting a example by investing in green technology, but said he could go further by cutting electrical consumption.

Simple steps, such as using the dishwasher only when full, turning off phone chargers at the mains when not in use and installing energy-efficient light bulbs would be more effective in reducing carbon dioxide emissions.

Money spent on fitting urban homes with wind turbines was largely wasted, and most other microgenerating technology had yet to prove itself, the panel of scientists said.

There were so many obstructions, such as other houses and tall trees, that urban wind turbines rarely got enough wind to make them cost-effective.

Luke Myers, of the University of Southampton, said that cities such as London were usually located in sheltered spots with low wind levels. The available wind was often too high to power household turbines, and unless they could be placed on the top of tower blocks, they were unlikely to contribute to cutting bills.

Dr Myers said that householders considering installing wind turbines were hampered further by a shortage of research into wind conditions in cities. “We really need measured wind data, but there’s never been the need for the wind speeds of Kensington until now,” he added. In the countryside, however, where homes were more exposed to the elements, wind turbines could make a substantial contribution to cutting electricity bills and reducing carbon dioxide emissions.

James Keirstead, a member of the decentralised energy group at Imperial College London, said the main benefit of siting wind turbines in towns and cities was to make residents more eco-conscious. He said it could have a “follow the leader” effect, reminding neighbours that altering their lifestyles could reduce carbon dioxide emissions. Similarly, he said, a study on the domestic use of solar panels had shown that the main effect was to make residents more conscious of energy consumption, encouraging them to use less.

The lesson, he told a briefing at the Science Media Centre in London, was that we had to consume less electricity. “The first thing we should do is get our demand down,” he said. The scientists said microgeneration technology such as wind turbines and solar panels had huge potential for reducing emissions, but that it needed to be developed further to be cost-effective. They suggested that the technology had been released on the market too early and, at a cost of between £1,500 and more than £10,000, was prohibitively expensive.

Jim Watson, from the energy group at the University of Sussex, said that the suitability for microgenerators varied from house to house. While wind turbines may be suitable for one, solar thermal power could be better for another.

“I don’t think there’s enough independent advice out there at the moment,” Dr Watson said. “Better funding of advice centres is very important.”

But he applauded microgeneration for promoting awareness of rising carbon dioxide levels. “Microgeneration has captured the imagination in a way that good old energy efficiency doesn’t,” he said. The Government recognised the potential of microgeneration but had done little to encourage it in practice. He cited the grants system, under which £80 million has been promised by the Government over three years to finance the installation of microgeneration systems. Only £6.5 million of this was being allocated to individual households, and the monthly share for March had been assigned within 75 minutes when it was made available last week.

The scientists criticised ground-source heat pumps for failing to pay for themselves within a reasonable time. They recommended solar thermal power, by which water is heated by solar panels, as the most proven microgeneration source, but said that it was too expensive for other household needs. Combined heat and power units, in which gas or bio-fuels are burnt, were considered an emerging technology.

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