Solar panel cost savings
Aug 2022
For London the headline numbers are:
Potential annual fuel bill saving: £414
Potential lifetime fuel bill saving: £10,160
Potential lifetime net benefit: £5,336
Potential lifetime CO2 saving: 19,815 kg.
For best results, move to Cornwall.
These numbers come from the Aug 22 Which?. Their calculations are done using the Energy Savings Trust's solar energy calculator. They assume a 4kW system on a roof with a 30-degree pitch. Don't be misled by apparent precisions of these figures: I'd treat them as back-of-the-envelope because they assume current prices for power (28.3p/kWh) and Smart Export Guarantee (4.1p/kWh). CO2 savings assume the grid's current carbon intensity, so savings will come down as the grid (we hope) decarbonises. All these numbers are likely to change.
Calculations also assume £5,419 installation costs, that the system lasts for 25 yrs, and that you have to replace the inverter twice (hence £1,450 maintenance costs).
There is more in the Aug 22 Which? Computing.
See also:
Which? Oct 2022 Is solar PV a good investment?