Over 10 years you can expect to have saved £2400, even allowing for paying for the panels.
Of course, it depends on a lot of things: how much they cost, how much electricity they generate, how much you use and when, how much you pay for electricity and how much you might get paid for electricity you export back to the grid.
Calculating all this isn’t necessarily hard, but everyone has different circumstances. Let’s run through one possible situation.
Solar panel costs
Despite the massive demand for solar panels and the various global problems, the cost of panels has plummeted.
A straightforward 4kW solar installation might cost about £5,000 – £6,000.
If the house is, for example, in Yorkshire and mostly south facing then it would generate approximately 3,400 kWh of electricity per year on average (kWh = kilowatt hour, the standard unit for electricity consumption).
The average household uses about 2,900 kWh of electricity per year, assuming they don’t have an EV or heat pump or anything else with high consumption like a hot tub.. Therefore, a 4kW solar panel system could, in theory, cover more than the average electricity needs.
However, it’s not that simple. The sun has an awkward habit of not shining at night, when everyone is at home, cooking and watching TV with the lights on, especially in winter. Meanwhile, for a lot of people, when it is shining on your panels to create electricity you are out at work. In this case you will perhaps only use 40% of your generation, exporting the rest to the grid.
Let’s do the maths on that, starting with the assumptions:
Current cost per kWh: £0.29
Export tariff per kWh: £0.15
Average electricity annual increase: 5%
Solar array output: 4 kWp
Specific yield kWh/kWp: 900
Estimated annual output: 3,600 kWh
Percentage solar used domestically: 40%
Estimated annual household consumption: 2,900 kWh
System cost: £5,000
So a mid-sized system for a typical family home should pay for itself in about 7 years, after which your electricity bills will be much lower, and stay lower even if electricity prices go up. Over 10 years you can expect to have saved £2400, even allowing for paying for the panels. It’s almost certainly worth taking out a loan, in fact.
If you decide to move house, you can probably add the cost of your panels to the asking price of your house.
How long will they last?
The average lifespan of a solar panel is around 25 to 30 years. Most reputable manufacturers offer production warranties for at least 25 years, ensuring that the panels maintain a high level of performance throughout this period.
Even after 30 years, solar panels can continue to generate electricity, albeit with some reduction in output due to gradual degradation. However, your panels might still be generating electricity in 40 to 50 years.
Sustainable Ferriby 