Solar Panel Payback Calculator
Work out your solar payback period, annual bill savings, SEG export income and 25-year profit — with or without a battery.
System & Installation
Batteries store surplus daytime solar for evening use, boosting self-consumption — but add to your up-front cost.
This calculator estimates generation using a simplified UK yield model (a typical kWh-per-kWp figure adjusted for orientation, roof angle and region). Actual output varies with shading, panel efficiency, inverter losses and local weather, so treat the results as a guide rather than a guaranteed figure — a solar installer’s site survey will give you an accurate estimate for your roof.
Energy Usage & Tariffs
Export rates vary by supplier and change often — always check the current rate before you commit.
Set automatically by the battery preset above — drag to fine-tune for your own daytime usage pattern.
25-Year Cumulative Profit
Calculation Breakdown
Battery vs No Battery
A fixed comparison using typical self-use rates (30% without a battery, 75% with one) on your generation and tariffs, so you can see whether storage is worth adding.
Solar Panel Payback Calculator UK 2026/27
Our Solar Panel Payback Calculator helps UK homeowners work out whether solar panels are worth the investment. Enter your system size, roof details, electricity usage and export tariff to see your expected generation, annual bill savings, Smart Export Guarantee (SEG) income, and how many years it takes to recover your installation cost — with an optional battery storage comparison built in.
How Much Do Solar Panels Cost in the UK in 2026?
Installation prices have settled since the supply-chain disruption of a few years ago. As of 2026, typical fully installed residential systems cost:
| System Size | Typical Installed Cost | With Battery Storage |
|---|---|---|
| 2 kWp | £5,000–£6,000 | £8,500–£10,500 |
| 3 kWp | £5,500–£7,000 | £9,000–£11,500 |
| 4 kWp | £6,000–£8,500 | £10,000–£14,000 |
| 6 kWp | £7,500–£10,000 | £12,000–£17,000 |
| 8 kWp+ | £10,000–£13,000 | £15,000–£20,000 |
Qualifying solar panel and battery installations in Great Britain currently benefit from 0% VAT until 31 March 2027, after which the rate is due to revert to 5%. That relief alone typically saves £1,000–£3,000 on a full system. Eligibility depends on the specific installation meeting GOV.UK’s energy-saving materials criteria, so it’s worth confirming with your installer that your quote already reflects the 0% rate.
How Solar Panel Payback Works
Your investment pays off through two income streams:
- Bill savings: electricity you use directly from your panels instead of buying from the grid (typically 25%–40% without a battery, or 65%–85% with one).
- Export earnings: surplus electricity sold back to the grid via the Smart Export Guarantee (SEG).
The payback period is how long it takes for these combined benefits to equal your installation cost. Most UK systems now pay back in 7–15 years, then provide pure profit for the remaining 10–18 years of a typical 25-30 year panel lifespan.
Smart Export Guarantee (SEG) Rates in 2026
Every UK energy supplier with more than 150,000 customers must offer an SEG tariff, but each supplier sets its own rate and terms — Ofgem does not mandate a minimum. Rates change often and have moved in both directions recently. Treat the figures below as an indicative guide and always check current rates directly with suppliers before you register.
| Tariff type | Typical Rate (p/kWh) | Notes |
|---|---|---|
| Standard fixed SEG | ~12p | A typical fixed rate from a major supplier |
| Competitive fixed SEG | ~15p | Some of the better rates require you to also import from that supplier |
| Time-of-use (Agile-style) peaks | 20–30p+ | Averages lower across the day; best with a battery |
| Basic/default SEG | ~4p | What you get if you don’t switch or compare |
Tip: Your SEG provider does not have to be the same company you import electricity from, so you can shop the export tariff independently and switch it without touching your main energy contract.
Is a Solar Battery Worth It?
Without a battery, most households only use 25–40% of what their panels generate, because peak generation happens midday while a lot of household demand happens in the evening. A battery stores that surplus for later use, typically lifting self-consumption to 65–85%.
Batteries add £3,500–£8,000+ to your upfront cost depending on capacity, which usually extends payback by a few years even though annual savings go up. The comparison table built into the calculator above shows both scenarios side by side using your own figures, so you can judge whether the extra outlay suits your usage pattern.
How Generation Estimates Are Calculated
This calculator (and the guide figures below) use a simplified UK yield model: a typical generation figure of around 850 kWh per kWp installed per year, adjusted by simple multipliers for roof orientation, pitch and region. This is a common rule-of-thumb used across the industry for early-stage estimates, but it is not an official or guaranteed output figure. Real-world generation also depends on shading, panel efficiency, inverter losses, local weather patterns and microclimate, so figures can vary meaningfully from one roof to the next. Use this calculator to compare scenarios and get a feel for payback — then confirm the real numbers with an MCS-certified installer’s site survey before committing.
Factors Affecting Solar Panel Performance
Roof Orientation
South-facing roofs generate the most electricity. South-east and south-west lose very little. East or west orientations cut output by roughly 15%, and north-facing roofs are not usually recommended, losing around 40%.
Roof Angle
The optimal angle for UK latitude is 30–35 degrees. Steeper 45-degree roofs perform well in winter; shallow 15-degree roofs lose a little efficiency but suit flat-roof tilted mounts fine.
Regional Variation
South-west England gets the most sunshine hours nationally. Scotland typically sees 10–15% less annual generation than southern England for an identical system.
Carbon Footprint Reduction
The UK grid has become significantly cleaner in recent years as coal generation ended and renewables expanded — average carbon intensity is now around 0.13–0.14 kg CO2 per kWh, down from roughly 0.45–0.50 kg CO2/kWh in the early 2000s. A typical 4kWp system generating around 3,400 kWh/year now avoids roughly 0.45–0.5 tonnes of CO2 annually — a smaller headline figure than a few years ago, but only because the grid itself is getting cleaner, not because solar is generating less.
Available Grants and Incentives
VAT relief: qualifying solar panel and battery installations in Great Britain currently benefit from 0% VAT until 31 March 2027, reverting to 5% after that date. Eligibility follows GOV.UK’s rules for energy-saving materials, so check your quote reflects this.
ECO4 Scheme: low-income and vulnerable households may qualify for free or subsidised solar and insulation measures. Check eligibility on the government website.
Boiler Upgrade Scheme: primarily for heat pumps, but some combined solar-plus-storage projects can align with a heat pump grant application.
Frequently Asked Questions
How much do solar panels cost in the UK in 2026?
A typical fully installed system costs roughly £5,500 to £7,000 for 3kW, £6,000 to £8,500 for 4kW, and £10,000 to £14,000 for a 4kW system with battery storage. Prices vary by installer, roof access and region. Qualifying installations in Great Britain currently benefit from 0% VAT until 31 March 2027.
What is the Smart Export Guarantee (SEG) rate in 2026?
SEG rates are set individually by each supplier and can change at any time — Ofgem requires larger suppliers to offer a tariff but doesn’t set the rate itself. As of 2026, competitive fixed rates are around 12 to 15p/kWh, with some of those requiring you to also be that supplier’s electricity customer. Basic default SEG tariffs can be as low as 4p/kWh, so it’s worth comparing current rates directly with suppliers before you register.
How long does it take for solar panels to pay for themselves?
Most UK solar installations pay back their installation cost within 7 to 15 years, depending on system size, self-consumption, electricity prices and export rates. Panels typically carry 25-year performance warranties, so a system that pays back in 10 years provides roughly 15 years of pure profit afterwards.
Is a solar battery worth it?
A battery raises self-consumption from around 30% to 70–85%, which increases annual savings but adds £3,500 to £8,000 or more to the upfront cost. Whether it’s worth it depends on your evening electricity usage, your import tariff, and how much your SEG export rate pays compared with what you’d otherwise pay to import that electricity back later.
Do I need planning permission for solar panels?
Most residential rooftop installations fall under permitted development rights. Exceptions include listed buildings, conservation areas, and some flats or maisonettes. Always check with your local planning authority before installing.
How long do solar panels last?
Modern panels carry 25-year performance warranties guaranteeing at least 80–85% output, and often keep working well beyond 30 years. Inverters usually need replacing after 10–15 years, typically costing £1,000–£2,000.
Does cloudy weather stop solar panels working?
No. Panels generate electricity from daylight rather than direct sunlight. Output drops to roughly 10–25% of clear-sky levels on heavily overcast days, but they still contribute meaningfully across the year.
What happens to my solar panels if I move house?
You can leave the system in place, which typically adds 4–6% to your property’s value, or pay £2,000–£4,000 to remove and reinstall them at a new property — which is often not economical unless the panels are new.
Will solar panels increase my council tax?
No. Solar panel installations are treated as improvements rather than structural changes, so they do not trigger a council tax band revaluation in the UK.