Use this list when comparing installers. Reputable companies welcome these questions — and answer them clearly.
About credentials and certification
Question 1
Are you MCS certified, and what's your installer number?
Good answer: Yes, plus the number on the spot. Verify at mcscertified.com. Vagueness or 'we'll sort it out later' is not acceptable.
Question 2
Are you NICEIC approved or NAPIT registered?
Good answer: Yes — they'll tell you which body and give you the number to verify.
Question 3
Are you TrustMark registered, HIES or RECC?
Good answer: Yes to at least one. These provide deposit protection and dispute resolution.
Question 4
How long have you been trading, and can I see your company registration?
Good answer: They give you the Companies House number. Verify at companieshouse.gov.uk.
About the installation
Question 5
Will your own employees carry out the install, or will it be subcontracted?
Good answer: Our own team. If they subcontract, they're transparent about who, vetting, and whether the subcontractor is MCS certified.
Question 6
Will you conduct a site survey before confirming the final price?
Good answer: Yes, before installation begins. Satellite-only assessment is fine for a provisional quote, but a physical survey is standard before installing.
Question 7
What brands of panels, inverter and battery will you use — and why?
Good answer: Specific brand names with a brief reason for the choice. Vague answers suggest products will be swapped based on margin.
Question 8
What's included — specifically scaffolding and DNO application?
Good answer: Both included. Some installers quote panels + install only and charge extra (£400–£800 for scaffolding) on top.
About warranties and aftercare
Question 9
What workmanship warranty, and who do I contact if there's a problem?
Good answer: A specific workmanship period (typically 2–5 years), a named contact, and a local phone number. 'Contact the manufacturer' is not acceptable for workmanship.
Question 10
What are the component warranties, and are they affected by who installs them?
Good answer: Panels 25–30 years, inverter 10 years, battery 10 years — and MCS-certified installation keeps them fully valid.
Question 11
Will I receive an MCS installation certificate, and when?
Good answer: Yes, within a few days of commissioning — without you having to chase.
Ask Alliant any of these questions
We answer all 15 in writing, with verifiable references.
About projections, grants and payment
Question 12
How did you calculate the estimated annual saving — what assumptions did you use?
Good answer: They walk through it: electricity rate, generation estimate by orientation and location, self-consumption rate, SEG rate. Honest installers include conservative and optimistic scenarios.
Question 13
Are you eligible to help me apply for Warm Homes Plan or ECO4 funding?
Good answer: Yes (if approved) and they check your eligibility proactively, not just to justify a sale.
Question 14
What deposit do you require, and how is it protected?
Good answer: 10–25%, protected via HIES or RECC. Full payment before installation is a red flag.
Question 15
What happens if you go out of business before completing my installation?
Good answer: Deposits protected under HIES/RECC, with a clear claims process they can describe.
Alliant's answers — in one place
Frequently asked questions
Is it rude to ask an installer these questions?
No. Solar is a £6,000–£12,000 investment lasting 25 years on your roof. Verifying credentials and warranties is reasonable due diligence.
What if an installer refuses to answer some of these?
That's your answer. Refusal or deflection tells you how they'll handle future warranty claims and aftercare.
Should I ask for the answers in writing?
Yes — at least the price inclusions, warranty terms, deposit amount and protection scheme. Verbal promises don't protect you if something goes wrong.
