Solar panel payback 2026 — UK: calculator

Calculated in pounds. By default the electricity price is 26.32p per kWh — Ofgem's GB average price cap unit rate for Direct Debit, 1 October – 31 December 2026; the cost is £1,697 per kW, the median of 4–10 kW installations in 2025/26 (DESNZ solar PV cost data), and the yield is 954 kWh per kWp a year (World Bank, UK average). Add your Smart Export Guarantee rate in the export field.

Example for the default values — change any field and the result updates.

Production in the first year, kWh4,770
Saving a year628 GBP
Simple payback, years13.5
Net saving over 25 years6,302 GBP

The result is an estimate, not financial or legal advice. Check the exact terms with the company.

Verified companies: Solar panels · United Kingdom

  1. 1Project Solar70/100
  2. 2SunGift Solar65/100
  3. 3Midland Solar61/100
  4. 4Green Energy Solar57/100

See the full ranking

How it is calculated

Production in the first year = size (kWp) × specific yield (kWh per kWp a year). The yield is the country average of the World Bank Global Photovoltaic Power Potential study (PVOUT, kWh/kWp/day × 365). It describes well-oriented, optimally tilted panels: a shaded or steep roof, or one facing east or west, produces less.

Saving a year = production × (self-consumption % × electricity price + (1 − self-consumption %) × export price). Power you use while the panels generate replaces power bought at the full tariff; the surplus is sent to the grid and earns the export price (0 if nobody pays for it).

Simple payback = cost ÷ first-year saving, without interest or tariff changes. Net saving over 25 years = the sum of 25 yearly savings, each 0.5% lower than the previous one (an assumed panel degradation), minus the cost. Maintenance, inverter replacement, financing and subsidies are not included — subtract a subsidy from the cost yourself.

Frequently asked questions

What is the Smart Export Guarantee?

The SEG is the scheme under which SEG Licensees pay small generators, including solar PV up to 5 MW, for power exported to the grid. The supplier sets the rate, contract length and terms; Ofgem requires the rate to be above zero. The calculator has no default export rate — enter your supplier's SEG tariff per kWh.

How much does solar cost in the UK?

The DESNZ solar PV cost data for 2025/26 show a median of £1,697 per kW for 4–10 kW installations and £1,780 per kW for 0–4 kW ones. The calculator uses £1,697 per kW when the cost field is 0 — your quote may differ.

Which electricity price does the calculator use?

26.32p per kWh — the GB average unit rate under the Ofgem energy price cap for Direct Debit customers from 1 October to 31 December 2026. Rates differ by region and payment method, and fixed deals differ from the cap — enter the rate from your bill.

Sources