How do I choose an installer in the UK?

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What to look out for and more.

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One of the most important things to check when you are choosing a solar installer in the UK is whether they are MCS certified.

An MCS-certified installer can provide the relevant MCS documentation on completion, which may be required for schemes such as the Smart Export Guarantee.

Beyond the MCS certification, a trustworthy installer should offer a clear, itemised quote, realistic performance estimates, and be transparent about who is actually carrying out the work.

Your starting point: check if the installer is MCS certified

If you're planning to install a rooftop solar and/or battery system, you're most likely also planning to claim tariffs from the Smart Export Guarantee or apply for other forms of support.

MCS (Microgeneration Certification Scheme) is the UK's official quality mark for small-scale renewable energy installations.

You need an MCS-certified installer to claim ECO4 or Warm Homes Plan support.
You need an MCS-certified system to apply for the Smart Export Guarantee.
Only certified installers can issue you a valid MCS certification on completion.

As of July 2026, there were 4,777 MCS-certified PV installers in the UK + Isle of Man. Your first filter is straightforward: ask for their MCS registration number and verify it directly, rather than taking a website badge at face value.

What to look out for in a quote

A robust quote should clearly break down these five items, at the minimum:

System specification: panel wattage and count, inverter model, battery capacity — not just a general system size, e.g. "10kW system", but the actual components.
Estimated annual generation and savings: ideally, this should include your roof's specific orientation, pitch and shading, not just generic regional averages.
Total cost: inclusive of 0% VAT where applicable.
Payback period and estimated returns: including the assumptions behind them, such as electricity prices, export rates and usage patterns in your household.
Warranty terms: make sure it's for each specific component—panels, inverter and battery separately, since the terms often differ by product/ supplier.

If a quote is vague or unclear on any of the above, or the savings estimates seem detached from your actual roof, make sure to ask more questions before signing.

Red flags worth watching out for

High-pressure sales tactics, e.g. same-day discounts that are only applicable on signing within a short timeframe
No physical site survey before a fleshed-out quote is issued
Vague/missing details on MCS certifications
Your roof's orientation or shading is not factored into savings estimates
No mention of warranty terms, or warranty periods that appear much shorter than others you're considering

Six questions to ask an installer before you commit

What is your MCS registration number? Can I verify it independently?
Will the workers on-site be your direct employees or subcontractors?
If a panel or inverter fails during the warranty period, what are my follow-up options? Who do I contact?
How was my savings estimate calculated and where was the information sourced from? Is it based on a regional average or my actual roof?
What does the upfront cost include and is anything billed separately?
What are the payment terms?

Battery systems add a layer of complexity

Battery installations need to consider inverter compatibility, safe integration with your consumer unit and correct sizing for your household's evening demand.

An installer with strong PV experience but limited battery experience can still get the panels right, but not necessarily the battery sizing or integration.

If you are considering a battery, it's worth checking specifically for an installer's battery installation track record, not just solar generally. The MCS database also includes filters for installers that also offer battery installations and other small-scale renewable technologies like heat pumps.

Get a free assessment on EnergyBrain

Our assessment tool, Emily, matches homeowners and people planning to install solar with installers in their area based on your rooftop assessment. This reduces the need to search independently and vet each installer from scratch, and provides you with a guide on what your specific roof's estimate should look like.

Frequently asked questions

Is MCS certification legally required?

It's not a legal requirement to install solar without it. However, it's required if you want to claim grants, access the Smart Export Guarantee, or have a valid installation certificate.

How do I verify an installer's MCS certification?

Ask for their registration number and check it against the official MCS installer database.

Should I get multiple quotes?

Yes. As with any major investment or purchase, comparing a few quotes side-by-side is the clearest way to spot inconsistencies in savings assumptions, pricing or warranty terms.

EnergyBrain's free assessment tool, Emily, gives you a personalised rooftop estimate first before connecting you with an installer local to your postcode. Compare quotes against your personalised assessment to make more informed decisions.

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