Disclaimers & Important Information

Last updated: 8 June 2026 · Applies to the Solar Credit Calculator website

Every number this tool produces is a modelled estimate, not a quote or a guarantee. This page sets out, in full, the assumptions, methods and limitations behind those figures, and the important caveats that apply when you use them. It is a companion to our Terms of Service, Privacy Policy and Data Retention & Deletion Policy. The calculator is for indicative estimation only and does not constitute financial, tax, investment or professional advice of any kind.

1Generation & savings: estimates only

All figures are modelled estimates based on your inputs, regional solar irradiance data (PVGIS / JRC SARAH-3), and assumed self-consumption rates. Actual system output will vary due to shading, roof condition, soiling, panel degradation, weather patterns, and changes in household occupancy or consumption.

2Panel degradation

Annual saving and payback figures account for real-world panel performance decline: an initial light-induced degradation (LID) of ~2% in Year 1, followed by an ongoing reduction of ~0.5% per year thereafter (midpoint of the typical 0.3–0.8%/yr range for high-quality monocrystalline panels). Savings shown reflect Year-1 output; cumulative projections and payback periods apply year-by-year degradation factors. After 25 years, a well-maintained system is expected to retain approximately 87% of its original rated output. These factors do not account for specific environmental conditions such as shading variation or UV exposure levels at your site.

3Tariffs, SEG export & standing charges

Electricity import rates, Smart Export Guarantee (SEG) export rates, and standing charges are based on the current Ofgem price cap and prevailing supplier tariffs, and are reviewed periodically. Your actual contracted tariff may differ significantly. The default SEG export rate shown reflects the highest-paying widely-available export tariff; a conservative view is available on the results page. Standing charges are a fixed daily cost and are not reduced by solar generation.

4Finance

Finance figures use a simplified amortising APR calculation for illustrative purposes only. Actual loan terms, APR, deposit requirements, and eligibility will depend on your lender, credit profile, and personal circumstances. Payback and 25-year projections apply your selected energy-price-inflation assumption (default +3%/yr) to each future year's saving, while finance repayments are held at their fixed nominal amount; actual future energy prices and tariff rates may differ materially from this assumption.

5Heat pump & electric heating transition

Where a heat pump transition is indicated, additional electricity demand is estimated assuming an air-source heat pump Coefficient of Performance (COP) of 3.0, a gas boiler efficiency of 85%, and that approximately 70% of gas consumption relates to space heating. This is an indicative estimate only. Actual heat pump electricity demand depends on your home's insulation standard, heat pump sizing, thermostat settings, and climate. Heat pump installation costs are not included in the solar cost estimate. Consult a qualified MCS-certified heat pump installer for accurate assessments.

6EV & EPC estimates

Electric vehicle electricity load estimates assume average charging efficiency. EPC-based consumption adjustments are approximations. Actual energy use depends on insulation quality, heating system, and behaviour, not EPC rating alone.

7Install cost estimates

Default installation cost estimates are benchmarked to current UK market quotes (2026), taken as the average of two pricing methods (a fixed-plus-per-kWp model and a quote-tool schedule). The estimate is presented as a ±10% range, rounded to the nearest £500. Actual costs vary by installer, location, roof complexity, and system specification. Always obtain a written quote from a qualified MCS-certified installer.

8Battery storage cost estimates

Battery storage cost estimates are benchmarked to current UK market quotes (2026), taken as the average of two pricing methods (all-in: equipment, installation and VAT). Costs vary by battery brand, chemistry, capacity, and whether it is installed alongside solar or retrofitted. Always obtain a written quote from a qualified MCS-certified installer.

9Not financial advice · not investment advice

⚠ Not financial advice · Not investment advice. This tool is provided for indicative estimation purposes only and does not constitute financial, tax, investment, or professional advice of any kind. The figures shown are illustrative projections and should not be relied upon as a basis for any financial decision.

Consult a qualified financial adviser before committing to any finance arrangement.

10Surveys, quotes & MCS-certified installers

Solar PV installations are a significant capital purchase. Always obtain a full structural survey, roof assessment, and a written quotation from a qualified, MCS-certified installer before entering into any agreement. MCS certification ensures compliance with industry standards and is typically required to access the Smart Export Guarantee.

11Governing terms & related policies

Your use of this calculator is governed by our Terms of Service, Privacy Policy and Data Retention & Deletion Policy. If anything here is unclear, please get in touch before relying on an estimate.