Are solar panels worth it? The real numbers for UK homes
Published 19 February 2026 · 8 min read
Solar panel companies will tell you the answer is always yes. It is not always yes. It depends on your roof, where you live, how much electricity you use, and when you use it.
This is the honest version. We will show you the maths, tell you when solar makes sense, and tell you when it does not.
What it costs
A typical residential system in the UK is 3 to 4kWp. That is 8 to 10 panels on your roof.
| System | Cost installed | Panels |
|---|---|---|
| 3kWp (smaller roof) | £4,500–£6,000 | 6–8 |
| 4kWp (most common) | £5,500–£8,000 | 8–10 |
| 5kWp (larger roof) | £7,000–£9,500 | 10–13 |
| 4kWp + 5kWh battery | £8,000–£11,000 | 8–10 |
Prices include VAT (0% on residential solar since 2022). Source: Renewable Energy Hub, Energy Guide, Federation of Master Builders. Prices vary by installer and region.
What you get back
Solar panels save you money two ways:
- Electricity you use yourself. Every kWh you generate and use is a kWh you do not buy from the grid. At Ofgem's current rate of 24.67p/kWh, that is the most valuable use of your solar electricity.
- Electricity you export. What you do not use goes back to the grid. Your supplier pays you for it through the Smart Export Guarantee (SEG). Rates vary: Octopus pays up to 15p/kWh, most others pay 3 to 12p/kWh. A typical average is around 12p/kWh.
This is why self-consumption matters so much. Using your own electricity saves you 24.67p/kWh. Exporting it earns you roughly 12p/kWh. Same sunshine, very different value.
How much electricity will you actually generate?
It depends on where you are and which way your roof faces. A south-facing roof in Brighton produces about 35% more than the same panels in Inverness. East or west facing roofs produce about 15% less than south.
| Location | kWh per kWp/yr | 4kWp output |
|---|---|---|
| Brighton (south coast) | 1,130 | 4,520 kWh |
| Bristol | 1,050 | 4,200 kWh |
| Manchester / Leeds | 920 | 3,680 kWh |
| Edinburgh | 870 | 3,480 kWh |
| Inverness | 837 | 3,350 kWh |
South-facing, 30-40° roof pitch. East/west facing reduces output by roughly 15%. Source: MCS Installer Standard Estimation Method, European Commission PVGIS.
The payback calculation
Take a 4kWp system in the middle of England. It generates about 3,800 kWh per year. You use half yourself and export half.
Payback period
After payback, the electricity is essentially free for the remaining 15 to 20 years of the panel's life.
What goes wrong
Solar companies rarely talk about these. You should know about them before you commit.
The inverter will need replacing
The inverter converts DC from the panels to AC for your home. It lasts 10 to 15 years, not 25. Budget £800 to £1,200 for a replacement around year 12. This is the main ongoing cost. The panels themselves have no moving parts and rarely fail.
Output drops over time
Panels degrade at roughly 0.5% per year. After 25 years they will still produce about 85% of their original output. Most manufacturers guarantee at least 80% at year 25. This is gradual and already factored into the payback calculations above.
You generate most when you need least
Solar output peaks in summer. Your electricity use peaks in winter (shorter days, more lighting, heating on). In December you might generate 100 kWh. In June, 500 kWh. If you are out during the day, much of the summer output gets exported at the lower SEG rate instead of saving you the full 24.67p.
Does a battery help?
A battery stores electricity generated during the day for use in the evening. Typical cost: £2,000 to £3,000 for a 5kWh battery, added to the panel installation.
It pushes your self-consumption from about 50% to around 70%. That means more of your electricity is valued at 24.67p instead of 12p. But the extra saving is modest:
The battery's own payback period is longer than its lifespan (10 to 12 years). On pure economics, the battery is marginal. It makes more sense if you are on a time-of-use tariff where you can charge cheaply overnight and avoid peak rates, or if you value backup power during outages.
When solar does not make sense
Be cautious if:
- Your roof faces north. You will lose 30 to 40% of potential output. The payback stretches past 15 years and the economics become questionable.
- Your roof is heavily shaded. Trees, neighbouring buildings, or chimneys casting shadows across the panels will significantly reduce output. Even partial shading on one panel can affect the whole string.
- You are planning to move within 5 years. You may not recoup the cost through a higher sale price, especially if the buyer does not value solar. That said, an improved EPC rating does add measurable value to a property.
- Your electricity use is very low. If you use less than 2,000 kWh a year, most of your solar output will be exported at the lower rate. The payback will be longer.
- You need a new roof first. If your roof needs replacing in the next 5 to 10 years, do that first. Removing and reinstalling panels costs £500 to £1,000.
When solar makes strong sense
- South-facing roof, minimal shading. You will get the most output and the fastest payback.
- High daytime electricity use. Working from home, electric vehicle charging, or running a heat pump all increase self-consumption. More self-use means faster payback.
- You plan to stay for 10+ years. The real value of solar comes after payback. Years 10 to 25 are essentially free electricity.
- Combined with a heat pump. A heat pump runs on electricity. Solar panels reduce the electricity bill. Together, they can cut your total energy costs dramatically, especially with the £7,500 BUS grant covering most of the heat pump cost.
What life looks like after payback
This is the part that gets glossed over. After year 8 to 10, the panels are paid off. You still have energy bills, but they look very different.
Take a household currently spending £2,500 a year on energy (gas and electricity combined). With a 4kWp solar system paid off and no battery:
Your annual energy costs, post-payback
You still pay for gas. You still pay standing charges. You still buy electricity on dark winter evenings. But roughly a third of your electricity comes from your roof, and the surplus earns you a small income.
If you also switch to a heat pump (replacing the gas boiler), the picture changes again. Your gas bill disappears entirely, replaced by a higher electricity bill, but one that solar significantly offsets. Some households with solar and a heat pump report total energy costs under £1,000 a year.
The point is: solar does not eliminate your energy bills. It cuts them by roughly a third on its own. Combined with other improvements, the reduction can be much larger.
The 25-year picture
Here is what a 4kWp system looks like over its full lifetime, for a typical home in central England:
| Conservative | Typical | |
|---|---|---|
| Installation cost | £8,000 | £6,500 |
| Inverter replacement (~year 12) | £1,200 | £1,000 |
| Total cost over 25 years | £9,200 | £7,500 |
| Annual saving | £700 | £780 |
| Total saving over 25 years | £17,500 | £19,500 |
| Net gain after 25 years | £8,300 | £12,000 |
| Property value uplift (est.) | +£2,000–£5,000 | +£2,000–£5,000 |
Accounts for 0.5%/yr panel degradation. Does not include a battery. Property value uplift based on EPC improvement research (1.5–2.5% per band).
Even the conservative scenario returns nearly double the investment. The risk is low because the panels have no moving parts, carry 25-year warranties, and the UK grid guarantees a buyer for your exported electricity through the SEG.
These figures assume electricity stays at today's price. It almost certainly will not. UK electricity prices have risen roughly 90% in five years. Your solar system's cost is fixed on day one. The value of what it produces goes up every time energy prices do.
Here is what the same 4kWp system returns depending on what you are paying for electricity:
| If electricity is... | You save | Payback | 25-yr net gain |
|---|---|---|---|
| 25p/kWh | £640/yr | 12.5 years | £8,000 |
| 28p/kWh (today) | £754/yr | 10.6 years | £10,900 |
| 35p/kWh | £890/yr | 9.0 years | £14,200 |
| 40p/kWh | £1,010/yr | 7.9 years | £17,300 |
| 50p/kWh | £1,280/yr | 6.3 years | £24,000 |
Based on a £8,000 total cost (installation + inverter replacement at year 12). 50% self-consumption, 0.5%/yr panel degradation. SEG export rate estimated at ~43% of the retail electricity rate. These are estimates. Nobody knows where prices will be in 2050.
At 25p, solar still works but it is a slower return. At 40p or above, the payback drops under 8 years and the 25-year gain is over £17,000. That is a better return than most savings accounts, and it is tax-free.
So, are they worth it?
If your roof faces roughly south and is not heavily shaded, and you plan to stay in your home for more than a few years: yes. The numbers are hard to argue with.
You spend £6,000 to £8,000 once. You get that back within 8 to 10 years. Then for the next 15 years, your roof generates free electricity. Over the full 25-year life of the panels, you come out £10,000 to £17,000 ahead, depending on what happens to energy prices. Your property is worth more. Your EPC rating improves. And every time there is another energy price rise, you are less exposed than your neighbours.
There are very few home improvements where you spend money, get it all back, and then keep earning a return for another 15 years. Solar is one of them.
It is not right for every home. If your roof faces north, if it is heavily shaded, or if you are moving soon, the numbers do not stack up. We have been clear about that. But for the majority of UK homes with a decent south-facing roof, this is one of the best financial decisions you can make.
What to do next
Start with your property. Your EPC, roof size, and location all affect the numbers. We calculate property-specific solar estimates for every home in England and Wales.
See what solar could save at your address
Enter your postcode to see your EPC rating, solar estimate, and available grants.
Check your homeAlready know your property? Read our full solar guide for more on installation, MCS certification, and choosing an installer. Or see whether you can run a heat pump without solar.