Solar is a great investment for some UK homes and a poor one for others. The variables that matter — roof orientation, your electricity usage, where you live, whether you'll add a battery — are all here in working calculators. Use them before you take a quote.
Typical fully-installed cost of a 4 kW system on a 3-bed UK home. 0% VAT applies until 31 March 2027.
Annual generation from a 4 kW south-facing system — covers most or all of an average UK household's usage.
Smart Export Guarantee rates by supplier. Octopus Outgoing and EDF generally pay best for exported power.
Self-consumption rate without and with a properly-sized battery. The single biggest payback lever after orientation.
Typical payback period for solar-only on a south-facing roof in southern England. Battery payback adds 4–6 years.
Standard performance warranty. Most modern panels still produce 80%+ of their original output by year 25.
Postcode-adjusted yield, SEG income, battery uplift, payback period, and 25-year savings.
Solar self-consumption uplift plus the time-of-use arbitrage your installer probably didn't mention.
Octopus Outgoing 15p, E.On Next 16.5p, EDF, OVO and more. Quick earnings estimator included.
0% VAT applies to everyone. ECO4, Warm Homes Local Grant and Home Energy Scotland may give you free or subsidised solar.
The honest answer to the question everyone asks. Three roofs where it pays back in under 7 years, and three where it doesn't.
If you're considering a heat pump alongside solar — what the £7,500 BUS grant covers and the new £2,500 air-to-air option.
Each page uses your city's real regional irradiance factor to give you a location-accurate payback estimate — not a national average that flatters the numbers.
Yes — even Scotland gets enough sunlight for solar to make economic sense, though payback periods are longer than in southern England. The UK receives roughly 60% of the solar irradiance of the equator, which is enough to make a 4 kW system generate 3,000–4,200 kWh annually depending on location and orientation.
The Feed-in Tariff closed in 2019. Today, the main support is the Smart Export Guarantee (suppliers must pay you for exported electricity, currently 4–15 p/kWh) and 0% VAT on installation until 31 March 2027 — saving roughly 20% on the standard rate. From April 2027, the new Consumer Loan Scheme will offer 0% interest loans.
A battery raises self-consumption from ~40% to 70–80%, which means you save more on imports — but it adds £3,000–£5,500 to the install. Whether it pays back in time depends on your evening usage pattern and whether you can pair it with a time-of-use tariff like Octopus Go (which lets you charge cheaply overnight too). Run the calculator with battery on/off to see the difference for your numbers.
Insist on it. Only MCS-certified installers can register your system for the Smart Export Guarantee, and many lenders/insurers require MCS for warranty cover. The MCS Installation Database (mcscertified.com) lets you verify any installer's certification before signing.
North-facing roofs, heavily shaded roofs, slate roofs in poor condition, and homes planning to move within 4–5 years. Also: rented properties (your landlord owns the panels and savings), and homes with very low electricity usage who'll export most of what they generate at low SEG rates.