How Many Solar Panels Do I Need? UK Solar Calculator
Work out how many solar panels you need, then see the savings, cost, and payback for that system. Most UK homes need around 10 panels (a 4.4 kWp system) to cover 80–100% of their electricity use, but the right number depends on your roof, region, and current bill. Enter your details below for a personalised estimate using regional UK solar irradiance data and current 0% VAT rates.
Last updated November 2026
Estimated 25-Year Net Return
£11,605
After system cost of £7,420 (0% VAT)
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Estimates based on region-level irradiance data (PVGIS), electricity at 26.32p/kWh (Ofgem price cap), your selected SEG rate, and 0% VAT on residential installs. Overnight charging assumes a 8p night rate on 150 days a year, with day use still at the price cap. 38% of output is used at home (this falls as the system gets bigger than your usage, and rises with a battery); the rest is exported. Actual results vary by exact location, roof pitch, shading, panel efficiency, and electricity price changes.
How many solar panels do I need?
A typical UK home needs 8–12 solar panels, equal to a 3.5–5 kWp system. The exact number depends on your electricity use, roof space, and region:
- 1–2 bedroom flat or small home: 5–7 panels (2–3 kWp)
- 3 bedroom house (typical): 10 panels (4–4.4 kWp)
- 4–5 bedroom house: 12–16 panels (5–6.5 kWp)
- Home with an EV or heat pump: 14–20 panels (6–8 kWp)
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How Much Can Solar Panels Save You in the UK?
Self-Consumption
Around 40% of the electricity your panels generate is used directly in your home, displacing grid electricity at26p/kWh. This is where the biggest savings come from.
Export Income
Surplus electricity is exported to the grid and paid at around 13–15p/kWh under the Smart Export Guarantee (SEG) depending on your supplier.
0% VAT
0% VAT on residential solar installations reduces your upfront cost significantly. A 4kW solar system typically costs £6,000–£7,800 fully installed, with the VAT exemption saving around £1,200–£1,600.
How much do solar panels save per month?
A typical 4.4 kWp solar panel system in the UK saves £45–£60 per month on average across the year. Monthly savings vary seasonally: £80–£110 in summer (May–August) when output peaks, £35–£55 in spring and autumn, and £12–£25 in winter (December–February). These figures include both self-consumption savings (avoiding 26p/kWh grid electricity) and export income (around 13–15p/kWh SEG for surplus). Annual savings total around £600 for a typical system.
What size system should you enter?
Most UK homes install a 4.4 kWp system (around 10 panels), which covers 80–100% of a typical 3-bed household's electricity use. Smaller flats often need 2–3 kWp, while larger homes with an EV or heat pump may want 6 kWp or more. Pick your system size above to see the savings, cost, and payback for that size.
For a full breakdown of how many panels different house sizes need, see our guide: How many solar panels do I need?
What assumptions does the solar calculator use?
These are indicative estimates. Actual performance depends on exact location, roof pitch and condition, shading, panel type, inverter efficiency, and electricity price changes over time. Adding battery storage increases self-consumption to 75-85% but adds to the upfront cost. See how generation varies by region on our regional solar irradiance map.
Frequently Asked Questions About Solar Savings
How much can solar panels save me in the UK?
A typical 4.4 kWp system saves around £600 per year, combining self-consumption savings (avoiding 26p/kWh grid electricity) and Smart Export Guarantee income (around 13–15p/kWh). Savings depend on your region, roof orientation, and how much electricity you use during daylight hours. Enter your details in the calculator above for a region-specific estimate.
What is the payback period for solar panels?
Most UK solar systems pay for themselves in 10–12 years. With 0% VAT keeping upfront costs lower, payback has improved in recent years, though it remains in the low teens for a standard no-battery system. Adding a battery lengthens payback slightly but increases lifetime savings by raising self-consumption to 75–85%.
How much are solar panels?
Solar panels in the UK cost approximately £1,500–£1,950 per kWp at 0% VAT. A typical 10-panel (4kWp) system costs £6,000–£7,800 fully installed. Prices vary by installer and equipment.
How much does a solar panel system cost?
A residential solar panel system in the UK costs £5,000–£11,800 depending on system size. The most popular 4kWp system (10 panels) costs £6,000–£7,800 installed. Adding a 5 kWh battery adds £2,500–£4,000.
What is the 25-year return on solar panels?
Over 25 years, a typical 4.4 kWp system returns around 2x the initial investment, roughly £15,000–£18,000 in total savings. After the 10–12 year payback period, the system generates effectively free electricity for the remaining 12+ years, while panel output degrades only around 0.5% per year.
Are solar panels worth it?
Yes. In the UK, a typical 4.4 kWp solar panel system pays for itself in 10–12 years and generates free electricity for 25+ years. With 0% VAT and Smart Export Guarantee (SEG) tariffs (around 13–15p/kWh), the 25-year return is typically around 2x the initial investment.
Are solar panels worth it in the UK?
Yes, solar panels are worth it in the UK. Despite the climate, the UK gets enough sunlight for solar panels to generate 80–100% of a typical home's electricity. With 0% VAT and Smart Export Guarantee (SEG) tariffs, payback is 10–12 years. Over 1,500,000+ UK homes have already installed solar.
Sources
- HMRC, 0% VAT on Solar Panels
- Ofgem, Smart Export Guarantee (SEG)
- Ofgem, Understanding Your Electricity Bill
- MCS, Certified Installer Directory
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.
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Get an Accurate Quote for Your Home
This calculator gives estimates. For an accurate quote based on your specific roof, get in touch with MCS-certified installers.