Ten questions to ask before signing a solar quote

Ask these before you sign

1. What specific yield (kWh/kWp/yr) is assumed, and for which orientation/tilt/shading?
2. What self-consumption % is in the savings table — and from which load profile?
3. Is the export rate today's tariff, a forecast, or a promotional figure?
4. Are savings gross or net of standing charges and tax?
5. What is included in the installed price (scaffolding, electrics, roof work, bird mesh)?
6. Inverter warranty and expected replacement — who pays labour at year 12?
7. Panel performance warranty curve — what residual output at year 25?
8. Who owns the system if financed — and what happens if you move?
9. Monitoring access — will you get granular generation and export data?
10. What happens if yield is 15% lower than the brochure? Ask for that sensitivity in writing.

Reproduce their headline payback in the solar payback calculator with your numbers. If you cannot, ask why their assumptions differ.

This page is general information, not advice. Get an independent survey before spending money.