How we check our numbers

Most solar sites throw around confident numbers with no source and no date. We do the opposite, because the numbers only mean anything if you can check where they came from. Here's exactly how we build every figure on this site.

Where our figures come from

We don't make numbers up, and we don't recycle stale ones. Each headline figure is traced to a primary source and stamped with the date it applied:

• The price of electricity you avoid comes from the Ofgem energy price cap — 26.11p/kWh for 1 July–30 September 2026.
• Generation, cost and payback ranges are built from the government-backed Energy Saving Trust guidance, cross-checked against live 2026 installer pricing.
• The 0% VAT rule comes straight from HMRC's VAT Notice 708/6: 0% on residential solar until 31 March 2027, then 5%.
• Export (Smart Export Guarantee) rates come from the suppliers' own pages and Ofgem's SEG scheme — e.g. Octopus Outgoing 12p (it was 15p until 1 March 2026), stamped "as at July 2026".
• Installer standards reference MCS and the Renewable Energy Consumer Code (RECC).

How the estimates are built

Our savings calculator and every worked example use the same transparent assumptions, shown on the page: about 950 kWh generated per kWp a year for a well-sited UK roof; a self-consumption rate of roughly 45–50% without a battery; a self-consumed unit worth about twice an exported one (~26p avoided vs ~12p earned); and install prices of about £1,500–£2,000 per kWp with 0% VAT. We show a range, never a single hero number, because your real figure depends on your roof, shading, usage and tariff — which only a survey can confirm.

Our no-fabrication promise

This is where we differ from a lot of the industry:

• We never invent reviews, star ratings, testimonials or fake "customers". If a number can't be traced to a real source, it doesn't go on the page.
• We quote ranges with the assumptions stated, and we say "confirmed at survey" — because that's the truth.
• We tell you when solar is not worth it. A north-facing roof, low bills, being out all day, or a house move within a few years can all sink the case, and we'd rather lose the enquiry than sell you something that won't pay back. See when solar is not worth it.
• We discredit the myths rather than repeat them — including the "solar adds 14% / £32,000 to your home" claim, which isn't robustly evidenced.
• We use honest, dated "why now" reasons only (the 0% VAT deadline, forecast panel-price rises) — never fake countdowns or "act today" pressure.

Who reviews this

The content is written and fact-checked by the SEO Dons editorial team against the primary sources above, and re-checked each quarter and after any Budget or Ofgem price-cap change, because these numbers move. Every page carries the date its rates applied. If you ever spot a figure that looks out of date, it's worth telling us — we'd rather fix it than leave a stale number up. Last reviewed: July 2026.

Want to see it in action? Read our straight answer on whether solar is worth it, or run your own numbers on the savings calculator.