A bright summer has driven up the returns households can make from solar panels on their roofs, the Telegraph has reported.
And despite cuts in the amounts paid for the electricity generated, which is paid through a levy on all energy bills, the industry claims returns of more than 12 per cent are still possible.
But the bold promises from salesman have also led to a rise in complaints from those who feel let down.
So far around 450,000 households have installed solar panel electricity systems, known as solar photovoltaics, which capture the sun’s energy and convert it into electricity. A further 2,000 systems are currently being installed each week.
The row triggered by Labour leader Ed Miliband’s promise of a 20-month utilities price freeze, with threats of blackouts, could prompt more households to reach for the solar brochures.
The Energy Savings Trust estimates a typical cost saving of £785 annually, in return for a £7,000 average investment in panels.
This compare to an average annual electricity bill of £479.
The Solar Trade Association puts the annual savings slightly higher at £823, largely because it has a higher estimate of how much energy households will use.
On this basis, the STA estimates a system will give a 12.5 per cent tax-free annual return over 25 years. The EST does not estimate returns but also does not dispute STA’s claim.
The EST admits its figures are based on optimum assumptions in a London postcode, where the sun shines more than elsewhere.
The calculator on its website shows the highest savings were in Cornwall, where they reached £739 annually. This dropped to £669 in South Warwickshire and £651 in Middlesbrough.