
Many people would save just £10 a year on their electricity bill by installing a wind turbine on their roof, according to a leading turbine technology firm.
This means that it would take 150 years for turbines- costing £1,500 - to save enough money to pay for themselves.
With UK wind speeds of 5.6m/s (18.3ft/s), many Britons would not benefit from high savings.
Chief of Windsave, David Gordon, told Panorama: "[Between] 4-6 metres, you'd save about £10 a year.
"Six metres onwards and you could save up to £50 to £100."