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.
Justin Rowlatt installed a wind turbine to save energy
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."
In Panorama's Go Green Or Else report, BBC journalist Justin Rowlatt spent a year trying to reduce his carbon footprint.
As part of a "carbon challenge" set by Professor Tim Jackson of Surrey University, to reduce his family's impact on the environment, Rowlatt decided to try to install a wind turbine as a way of generating carbon-free electricity.
Windsave offered him one, but seven months later - and three days before it was due to be installed - the company withdrew its offer saying his house was not suitable.
After the offer was withdrawn, David Gordon explained there was not enough wind at Rowlatt's London home.
Go Green Or Else will be aired on BBC One and on this site on Monday 5 March at 2030.