Step 1: MCS Certification - The Non-Negotiable Baseline

MCS (Microgeneration Certification Scheme) is the UK's quality mark for small-scale renewable energy systems. It certifies both the installer and the installation itself, confirming the work meets defined technical standards for solar PV design and installation. Without it, the installation simply does not meet the accepted UK benchmark for domestic solar.

MCS certification matters beyond quality assurance for one very practical reason: you need it to access the Smart Export Guarantee (SEG), the scheme through which energy suppliers pay you for surplus electricity exported back to the grid. Only MCS-certified installations qualify. Skipping this check does not just risk a poor installation. It could cost you years of export payments.

Always verify MCS status directly using the official MCS Find an Installer postcode search rather than taking a company's word for it. Check all three of the following:

The certification is current and has not expired

It covers solar PV specifically, not just other technologies

The business name on the MCS register matches the name on your quote exactly

A trustworthy company will share their MCS number immediately and without prompting. For more on why this matters, see our Solar Power in the UK: A Practical Guide.

Step 2: Supporting Accreditations That Add Another Layer of Assurance

Beyond MCS, two schemes add meaningful consumer protection worth checking:

TrustMark

- a government-endorsed quality framework confirming the business has been vetted for workmanship and customer service standards, with access to a formal complaints route if problems arise

RECC (Renewable Energy Consumer Code)

- sets conduct rules specifically for companies selling renewable systems to domestic customers, covering honest quotations, cancellation rights, deposit protection, and independent dispute resolution

Also check whether the installer holds NICEIC or NAPIT electrical registration. These confirm the electricians carrying out the work are assessed for competence and authorised to issue an Electrical Installation Certificate on completion. You should always receive this certificate after installation. It confirms electrical work complies with BS 7671 and is your proof of compliance for insurance and conveyancing purposes.

A reliable practical test: Ask each installer upfront for a complete list of every certificate and document you will receive after sign-off. A trustworthy company will answer immediately and in full. Vague or evasive answers here are worth noting. For a full breakdown of what to expect, see our Comprehensive FAQ.

Step 3: Using Official Directories and Postcode Finders

Several reliable UK tools exist for finding vetted local solar PV installers:

MCS Find an Installer postcode search

- the most authoritative starting point; every result is MCS-certified

Solar Energy UK member directory

- lists established UK solar companies

Manufacturer-certified directories

such as the SolarEdge installer finder - useful if you have a preference for specific equipment, but treat these as a secondary check rather than independent accreditation

Cross-referencing two or more directories quickly surfaces installers who appear consistently across different sources and hold multiple recognised accreditations.

How a vetting service removes the research burden entirely

Running each company through multiple databases, checking expiry dates, and cross-referencing names takes time. Go Solar UK does all of this pre-screening for you, connecting homeowners only with MCS-certified local installers, providing a bespoke system design tailored to your roof and energy use before any quotes are presented, and funded by installers rather than by you.Learn more about

how the service works

See the full

benefits of comparing quotes through Go Solar UK

Step 4: Checking Reviews, Companies House and Real-World Track Record

Companies House

This is one of the most important and most overlooked checks. Search the exact legal name of the company on your quote at Companies House and look for the following:

Date of incorporation

- a brand new company taking large contracts is a warning sign

Directors

- check for serial phoenixers who close one company and immediately reopen under a new name

Previous company names

- repeatedly changing name can mean trying to shed a bad reputation

Filed accounts

- persistent late or missing accounts suggest a poorly run business

Reading reviews for patterns, not just star ratings

A single poor review rarely tells you much. What matters is whether the same complaint appears repeatedly across different platforms. Check all of the following:

Google Business Profile

- look for reviews spread over time, not a burst of five-stars in one week, and pay attention to how they respond to negative feedback

Trustpilot

- free to list and widely used by solar installers; look for volume and spread over several years

Checkatrade and Which? Trusted Traders

- these paid schemes involve vetting, but not being listed does not mean a company is bad as membership fees are significant

Defensive or dismissive responses to complaints are as revealing as the complaints themselves.

Requesting references from recent installations

Ask each shortlisted installer for two or three references from domestic solar installations completed within the past 12 months. When you speak with those references, ask the following:

Did the installation run to the agreed schedule?

 Was all promised documentation delivered on completion?

 How did the company handle any post-installation issues or queries?

A reputable installer will offer references readily and without hesitation. Reluctance or a promise to get back to you that never materialises is itself a red flag.

Step 5: What an Honest Solar Installation Quote Looks Like

A trustworthy quote is fully itemised. It should clearly state every one of the following:

• System size in kWp
•  Make and model of panels and inverter
• All mounting hardware and associated costs
•  Labour, scaffolding, and DNO application handling as separate line items
•  Electrical certification and monitoring or aftercare costs, itemised separately
•  Battery storage priced separately if included, never bundled into a single figure

Compare quotes on a per-kWp basis rather than total price alone. Divide the total installed price by the system size in kWp to get a like-for-like benchmark. The MCS-based UK average for 2026 sits at approximately £1,686 per kWp. A significantly cheaper quote often reflects fewer panels, a lower-grade inverter, or costs excluded from the headline figure that will surface later.

Each quote should also include estimated annual yield and projected SEG earnings, with assumptions clearly stated including roof orientation, shading, and local irradiance figures. This allows you to compare savings projections fairly across installers.

Documents every quote should include in writing

Alongside the itemised quote, request all of the following before signing anything:

• Equipment specification sheets for panels and inverter
•  Panel and inverter warranty documents
•  Workmanship warranty terms in full
• Written installation timeline with milestones from survey through to system activation

Never proceed on a verbal quote or a single-page summary. If an installer seems reluctant to put the full details in writing, that tells you something important about how they operate. Read our How It Works page for more on what the process should look like.

Step 6: Red Flags, Doorstep Scams and Rogue Traders

Solar and retrofit doorstep scams are a real and growing problem in the UK. Knowing the warning signs before a salesperson is standing on your doorstep gives you a significant advantage.

Doorstep red flags - close the door if you see any of these

Unsolicited, high-pressure doorstep visit or cold call with "today only" pricing or "you must sign now to qualify"

 Claims of "free solar", "no cost to you", or "special government scheme ending this week"

 Salesperson cannot clearly state who they work for, or implies they represent your energy supplier, your council, or the government

 Price is suspiciously cheap or wildly above other quotes, with vague explanations for either

 Refusal to leave a written quote, brochure, or contract for you to read in your own time

 Pressure to hand over ID, bank details, or sign a finance agreement on a tablet on the doorstep

 Claims of being "equivalent to MCS" or "MCS approved" without being able to provide a certificate number

If two or more of these happen, close the door and do not sign anything.

Credential red flags

Vague or evasive answers about MCS status, or reluctance to share certificate copies

 No physical address on quotes, or only a mobile number provided

 Large upfront deposit requested before a proper survey has been completed

 The company name on the quote does not match the name on Companies House or the MCS register

 Brand new company with no reviews, no track record, and no references

Quote and contract red flags

No make or model numbers for panels or inverter, just generic descriptions

 Warranty terms left unstated or described only verbally

 No clarity on who handles the DNO application

 No named project contact from survey through to completion

 Finance terms that rely entirely on "your savings will cover the payments" with no numbers to back it up

This ambiguity is often deliberate. It gives rogue traders room to substitute inferior equipment, add charges after signing, or walk away from problems because nothing was committed to in writing. Legitimate solar panel companies will always give you time to compare quotes and will never pressure you to sign on the day.

There are qualified, MCS-certified solar installers operating in every region of the UK. You do not need to settle for a company that cannot answer basic questions clearly. If something feels wrong, remove them from your shortlist. For more guidance see our FAQ and our full Solar Power UK Guide.

Step 7: Making Your Final Choice and Signing With Full Confidence

By this stage, you have checked credentials, reviewed feedback patterns, requested references, and compared itemised quotes on a per-kWp basis. Before committing, place your shortlisted proposals side by side and ask each installer these three final questions:

Who will actually be on site?

Are they directly employed or subcontracted, and do they hold personal MCS certification?

What exactly does the workmanship warranty cover, and for how long?What is the precise timeline from contract signing to system activation?A company that can answer all three clearly and in writing has thought through the delivery of your installation properly. One that gives vague or verbal-only answers to any of them should move down your shortlist immediately.Price should be the last factor you weigh, not the first. The cheapest quote on your shortlist rarely represents the best value once warranties, documentation, component quality, and afterercare are factored in properly. A system installed correctly by an accredited team, backed by solid warranties, and supported by a company that actually picks up the phone afterwards will outperform a marginally cheaper alternative across its 25-year lifespan in almost every case.

Your next step: a shortlist without the legwork

To recap the framework:

Verify MCS certification and electrical accreditation

 Use official directories or a pre-screening service to build your initial shortlist

 Check Companies House and review patterns across multiple platforms

 Request recent references and speak to them directly

 Compare itemised quotes on a per-kWp basis

 Recognise red flags early and remove any company that cannot answer basic questions clearly

 Confirm all key documents before signing

 Make your final decision based on credentials and value, not price alone

Follow these steps and you will not be caught out by a company that looks credible on the surface but cannot deliver.

For homeowners who want the shortlist without the legwork, Go Solar UK connects you with pre-screened, MCS-certified local solar installers, manages the quote comparison process for free, and does it all without obligation or sales calls chasing you afterwards. Find out more on our About Us page, or if you have specific questions visit our Comprehensive FAQ to see exactly how the service works.

Download the Free Go Solar UK Due Diligence Checklist

Everything in this guide has been condensed into a single printable checklist you can take with you when meeting installers or reviewing quotes. Tick off each item before you sign anything.

Download the Free Checklist (PDF)