Rooftop solar can save about £450 a year in cloudier parts of Britain

Households in Great Britain face high energy bills because wholesale electricity prices have risen. Installation costs for solar panels have fallen, and demand for rooftop systems has increased.

Analysis for the Guardian by Recharge Renewable finds rooftop solar can save about £450 a year in the cloudiest regions. In brighter parts of southern England the same method puts savings between £571 and £618 a year.

The analysis used the typical electricity output from a standard, south-facing 4kW rooftop system, assumed households use 50% of generation, and adjusted figures for 14 regions using satellite measures of annual sunshine. Rising wholesale prices and lower installation costs have made the potential savings larger in recent years.

However, a typical 4kW system costs about £7,000 after the government removed VAT for solar upgrades. The company warned north-facing or shaded roofs will not match a modelled south-facing array, calculations exclude a battery, and the stated value is of units displaced rather than a finished bill.