Five Questions to Ask a Potential Solar Installer
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Comparing solar quotes is much easier when you ask every installer the same handful of questions. These five cut straight to what matters — quality, price, design and aftercare — and the answers quickly reveal who is worth your trust.
1. Are you MCS-certified, and what is your certificate number?
This is non-negotiable. The Microgeneration Certification Scheme is required for you to claim Smart Export Guarantee payments, and it underpins installation quality. A reputable installer will give you their MCS number without hesitation, and you can verify it on the official MCS register. Ask too whether they belong to a consumer code such as RECC or HIES, which adds deposit and workmanship protection. If a company is evasive on either point, that tells you what you need to know. See accreditations explained.
2. Is the price fully inclusive, with 0% VAT applied correctly?
Ask for a single, all-inclusive figure covering panels, inverter, any battery, mounting, scaffolding, wiring, the network operator notification and commissioning. Confirm that the 0% VAT relief (which runs until 31 March 2027) has been applied to the qualifying work, and be wary of quotes that split off an "electrical upgrade" that might attract standard-rate VAT. A clear, single price is the only way to compare quotes fairly. See our cost guide.
3. How have you designed the system for my home specifically?
A good installer designs around your roof and your electricity use, not a generic template. Ask what system size they recommend and why, how they have accounted for shading and roof direction, what annual generation they expect, and — if a battery is included — how they sized it to your evening usage. Vague answers, or pressure towards the largest possible system regardless of your needs, are warning signs. The right system is the one that matches how you actually live.
4. What warranties apply, and who do I call if something goes wrong?
There are several overlapping warranties: the panel product and performance warranties, the inverter warranty, any battery warranty, and the installer's own workmanship guarantee. Ask for the length of each and, crucially, who is responsible for honouring them. An installer likely to still be trading in ten years, backed by a consumer code, gives real peace of mind. Find out the process for reporting a fault and how quickly they respond.
5. What happens after installation?
Good aftercare separates the best installers from the rest. Ask what you will receive on completion — your MCS certificate (needed to register for export payments), warranties and a handover pack — and how you will monitor your system's output to confirm it is performing. Check whether they help you register for the Smart Export Guarantee, and what ongoing support or maintenance they offer. A company that disappears the moment the scaffolding comes down is one to avoid.
Use the same five every time
Put these five questions to each installer you contact and note the answers side by side. Combined with at least three quotes, this simple discipline makes a five-figure decision far less daunting — and dramatically reduces the chance of an unhappy surprise later. For the wider context, read how to choose a solar panel installer.
A bonus question: how will you handle the network operator?
Connecting solar — and especially a battery — to the grid involves your local Distribution Network Operator (DNO). For most domestic systems the installer simply notifies the DNO after installation, but larger systems or batteries may need permission before work begins. A competent installer manages this process for you and knows which route applies. Asking how they will handle the DNO is a quietly revealing question: those who do this routinely answer confidently, while those who look blank may be less experienced than they claim.
Watch how they answer, not just what they say
Beyond the content of the answers, pay attention to the manner. A trustworthy installer welcomes scrutiny, explains trade-offs honestly, and is comfortable saying when something is not ideal for your home. High-pressure tactics, reluctance to put things in writing, or irritation at reasonable questions all point the other way. You are about to trust this company with a five-figure investment fixed to your home for decades; the quality of the conversation now is a fair preview of the aftercare later.
Bringing it all together
Ask the same five questions of every installer, note the answers side by side, and combine that with at least three written, all-inclusive quotes. This simple, repeatable process turns a daunting decision into a manageable comparison and dramatically reduces the risk of an unhappy surprise. For the wider picture, read how to choose a solar panel installer and our guide to accreditations.
Make the questions your own
Print or save these questions and take them to every conversation. They are deliberately simple, but used consistently they expose the differences between installers that glossy brochures hide. Quality, transparent pricing, tailored design, solid warranties and genuine aftercare are what you are really buying, and these five questions get straight to all five. Combined with three written quotes, they turn choosing a solar installer from a leap of faith into a clear, evidence-based decision.
Keep the answers on record
Write the answers down, or ask the installer to confirm the key points by email. Having the system size, expected generation, equipment, warranties and aftercare commitments in writing protects you later and makes the final comparison between companies genuinely like-for-like. It also signals that you are a careful buyer, which tends to bring out the best in a reputable firm and to deter the kind that relies on vagueness.
Treat these five questions as your standard script, and each conversation becomes a fair test rather than a sales pitch to survive. The installers worth choosing will appreciate a well-prepared customer; the rest will reveal themselves soon enough.
Done consistently, this simple routine takes the anxiety out of a big decision and leaves you confident you chose well.
