Free Eco Home Calculators

Solar Savings Calculator

1 min read Last updated 20 May 2026
Quick answer A typical UK 4 kWp solar PV system generates around 3,800 kWh per year and saves £550-£900 annually depending on self-consumption. At a 2026 install cost of around £4,400 and a Smart Export Guarantee tariff of 7p per kWh exported, payback is typically 7-10 years.

The Solar Savings Calculator estimates how much electricity a rooftop solar PV system could generate at your home, what it would cost to install at 2026 market rates, and how long it would take to pay back. The calculation is based on your roof size, orientation, UK region (which determines solar irradiance) and your current electricity bill.

Solar Savings Calculator

Estimate your savings from solar panel installation based on your roof and energy usage.

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Approximate area of south-facing roof space.

See 20 real-world examples

Each link below runs this calculator with real UK city and property inputs and publishes the exact computed savings, payback time, install cost and CO2 figures.

Browse all calculator examples →

How this calculator works

We calculate system size as roof area × 0.18 kWp/m² (modern monocrystalline panels at ~180W/m²). Annual generation uses regional solar irradiance from MCS data: 1,050 kWh/kWp/year in southern England down to 820 kWh/kWp/year in Scotland. Orientation factors apply (south = 1.0, east/west = 0.80). We assume 40% self-consumption (the rest is exported), 24.5p/kWh import savings (Ofgem cap 2026) and 7p/kWh SEG export earnings.

Sources & references

Frequently asked questions

How accurate is this solar savings calculator?

The figures are typically accurate to within ±15%. Real-world generation depends on shading, panel angle and panel make/model, none of which the calculator captures. For a binding figure, a Microgeneration Certification Scheme (MCS) installer will produce a Standard Assessment Procedure (SAP) generation estimate based on a site survey.

What is the average solar panel cost in the UK in 2026?

A typical 4 kWp system installed by an MCS-certified installer costs around £4,400 in 2026, working out at roughly £1,100 per kWp fitted. Premium tier-1 panels with hybrid inverters add 10-20%.

Do I get paid for solar electricity I export?

Yes — through the Smart Export Guarantee (SEG). Most large suppliers offer 5-9p per kWh exported. Octopus Outgoing, E.ON Next Export and EDF Export+ are typically near the top of the market.

Do I need planning permission for solar panels?

Most UK domestic solar installs are covered by permitted development rights and need no planning permission. Listed buildings, conservation areas and properties in Areas of Outstanding Natural Beauty (AONBs) are exceptions.

How long do solar panels last?

Tier-1 panels are typically warrantied for 25 years at 80%+ output and have a working life of 30+ years. Inverters last 10-15 years and usually need replacing once during the panels' lifetime.

Tool: Solar Savings Calculator. Last reviewed: . Figures based on Ofgem price cap, gov.uk grant guidance, and Energy Saving Trust advice. Verify scheme eligibility with your installer before commissioning work.