Solar Quote Questions to Ask an Installer

You do not need specialist vocabulary to test a solar quote. Ask clear questions about the design, assumptions, installed price and aftercare, then request the important answers in writing.

Questions about the roof and design

1. Why have you chosen this system size and panel count?
2. Can I see a scaled roof layout with the exact panel dimensions?
3. How did you model direction, pitch and shading?
4. What annual generation in kWh do you predict, and which method produced it?
5. Why is this inverter size and string design suitable?

Questions about cost and savings

6. Is the shown price the complete installed price including VAT, scaffolding and electrical work?
7. Which items are provisional or excluded?
8. What import price, export rate and self-consumption percentage are in the savings model?
9. Does the calculation assume electricity-price inflation?
10. Are inverter, battery or maintenance replacements included?

Questions about a battery

11. What are the usable capacity and continuous power?
12. What are the round-trip efficiency, cycle and throughput warranty terms?
13. Can I see the panel-only quote using the same assumptions?
14. Does backup work during a grid outage, and which circuits would it support?
15. Can the battery work with the proposed tariff without handing over unwanted remote control?

Questions about installation and protection

16. Can I verify the installer and installation company in the MCS directory?
17. Who handles the DNO notification or application and the export MPAN process?
18. Which deposit, workmanship and product protections apply?
19. Who is responsible if the roof leaks or monitoring stops?
20. What documents, certificates, manuals and warranties will I receive at handover?

How a useful answer sounds

A useful answer gives a number, method, product, responsibility or written exclusion. “It depends” can be honest when followed by what it depends on. A vague promise, unexplained payback, invented deadline or refusal to show assumptions is a reason to pause.

Before the appointment ends

Ask for the quote, design, forecast and contract to take away. Do not rely on a sales screen that disappears. Compare at least the system boundary and assumptions using the 12-point quote comparison.

Next steps

• Check documents with the solar quote checklist.
• Read how to verify an MCS installer.
• Request a home-specific quote when you are ready to compare a real design.