A bad solar quote doesn't just waste your time — it can cost you thousands of pounds in an overpriced system, a poorly designed install, or lost access to government export payments. Knowing the red flags before you invite anyone through the door is the single most powerful thing you can do.
Solar is a serious purchase. A typical UK system costs between £5,000 and £10,000 fully installed in 2026 — and with that level of money on the line, a little scepticism is healthy. This guide runs through the tactics some installers use to rush, confuse or overcharge homeowners, and what a genuinely good quote should look like instead.
Red flag 1: The "sign today" push
This is the oldest trick in the book, and it is still the most common. A salesperson sits in your living room and tells you the price is only available if you sign the contract tonight. Maybe there's a "cancellation slot in your area" that conveniently needs filling. Maybe it's a "limited-time government scheme" (which almost certainly doesn't exist in the form described).
Legitimate installers do not knock thousands of pounds off a quote just because you agree to sign on the spot. If a price can't be honoured tomorrow, it was inflated to begin with. The pressure is designed to stop you comparing quotes with anyone else — because a confident, reputable company is happy for you to do exactly that.
What to do: Thank them for their time, say you'll be in touch, and walk away. Then get at least two other quotes before deciding anything.
Red flag 2: Vague or missing equipment specifications
A solar quote that says "Tier 1 panels and a 5kW inverter" is not a specification — it is a blank cheque. Phrases like that let an installer swap in whatever panels and inverter are cheapest on the day of installation, and you'd have no contractual leg to stand on.
A properly written quote will name the exact panel model (including wattage), the inverter make and model, and — if a battery is included — the battery model and usable capacity in kilowatt-hours. Those product names matter because both the panels and the inverter must appear on the MCS Product Directory for your installation to be properly certified. If either is missing from that list, your installation certificate can be invalidated.
The equipment specification should also come with warranty details. Panels typically carry 25-year product warranties; inverters usually come with 10–12 years. The workmanship warranty — covering the installation itself — is separate, so check that's explicitly stated too.
What to do: Ask for the exact make, model and wattage of every component in writing. If the installer won't provide it, move on.
Red flag 3: No physical roof survey before the quote
A desktop estimate based on satellite imagery is a reasonable starting point — but it is not a final quote, and it should never be presented as one. A proper installation requires someone to physically visit your home, check the roof structure (including the rafters in the loft), inspect your consumer unit (fuse box), and assess any shading from trees, chimneys or neighbouring buildings.
MCS standards require a formal design assessment that includes shading analysis and an energy yield estimate. An installer who's never set foot on your roof cannot produce a compliant design — which means anything they sell you on that basis is a guess dressed up as a quote.
What to do: Never sign a contract with a company that hasn't completed a physical site survey first. The survey should be free and no-obligation.
Red flag 4: Savings claims that look too good to be true
Solar savings vary enormously depending on your electricity usage, roof direction, how much you're home during the day, whether you have a battery, and the tariff you're on. Anyone who tells you that you will save a specific fixed amount per year — or promises payback in three to four years — is giving you a sales pitch, not an honest projection.
For context, a typical 4kW system might reduce annual electricity costs by around £400 to £650 before export payments are considered. On top of that, the Smart Export Guarantee (SEG) — the government-backed scheme that pays you for surplus electricity sent back to the grid — can add further income. Flat-rate SEG tariffs from major suppliers currently run from around 10p to 15p per kWh exported, though rates change and you should compare them before signing up. You need an MCS-certified installation and a smart meter to qualify. For a full breakdown, see our guide to Best Smart Export Guarantee Rates UK 2026.
The red flag isn't a confident installer who explains their assumptions — it's one who inflates the electricity price used in their model, assumes unrealistically high self-consumption, or simply refuses to show you how they arrived at the figures.
What to do: Ask for the assumptions behind any savings estimate in writing: the electricity unit rate used, the assumed percentage of self-consumption, and the system's projected annual generation in kWh. If they can't or won't provide those, the numbers are fiction.
Red flag 5: No MCS certification
The Microgeneration Certification Scheme (MCS) is the UK's national quality standard for solar PV installations. It certifies both the installer and the products used. Without a valid MCS installation certificate, you cannot register for SEG export payments — meaning you'd be giving away surplus electricity to the grid for free. Some home insurers also require an MCS certificate, and finance companies may use MCS status to determine whether you qualify for their best rates.
MCS impersonation — where a company claims to be certified but isn't — does happen. You can verify any installer's current certification status directly on the MCS website at mcscertified.com. This takes about 30 seconds and is worth doing before any further conversation.
What to do: Search the installer's company name on the MCS Contractor Database before you agree to a survey. If they're not listed, don't proceed.
Red flag 6: A single lump-sum price with no breakdown
A trustworthy quote separates costs clearly: panels and equipment, inverter, mounting hardware, scaffolding, labour, and any electrical upgrade work needed at your consumer unit. A single undifferentiated number makes it impossible to compare like-for-like with other quotes, which is often the point.
On payment terms: a reasonable deposit is typically 10–25% upfront, with the balance due only on completion and successful commissioning. A company asking for full payment before installation starts is a serious warning sign.
One more thing worth checking: who actually does the work. Some sales companies take your order and then subcontract the installation to whoever is cheapest that week. Ask directly whether the people visiting your home are employed by the company, or whether the work will be passed to a third party.
What a good quote actually looks like
A quote you can trust will include: the exact system size in kWp; named panel, inverter and battery models; all component and labour costs itemised; panel and inverter warranty terms; a workmanship warranty from the installer; a site survey report; a projected annual generation figure with the assumptions shown; and confirmation of MCS certification. It won't pressure you, it won't expire at midnight, and the installer will actively encourage you to compare it against other quotes.
To understand what a fair price looks like for a system of your size — so you can spot an overpriced quote the moment you see one — take a look at our honest breakdown of Solar Panel Payback Time UK 2026 before you start talking to anyone.
How FairSolar fits in
FairSolar connects homeowners with vetted, MCS-certified local installers. We don't send you a single quote from a single company and hope you don't notice — you get multiple quotes so you can compare them properly. We're free to you as a homeowner, and we're transparent about how the service works (you can read more at how FairSolar is paid). If any installer in our network uses pressure tactics or refuses to provide a full written specification, we want to know about it.
When you're ready to start comparing, get your free, no-obligation quotes here. It takes about two minutes and you're under no obligation to proceed with anyone.
Frequently asked questions
How do I know if a solar quote is good value?
Compare the price per kilowatt-peak (kWp) of installed capacity. In 2026, most standard domestic systems are coming in at roughly £1,500–£2,200 per kWp fully installed. A quote significantly above that range warrants scrutiny; one dramatically below it warrants equal suspicion. Always get at least three quotes and make sure they all specify the same system size and equipment so you're comparing like-for-like.
What are the signs of a cowboy solar installer?
The main warning signs are: pressure to sign on the day; no physical roof survey before quoting; a quote that doesn't name the actual panel and inverter models; savings claims with no explanation of the assumptions behind them; no MCS certification (check at mcscertified.com); and a request for full payment upfront before any work begins. Any one of these should give you pause; more than one and you should walk away.
Should I sign a solar contract on the day?
No. There is no legitimate reason to sign a solar contract the same day a salesperson visits. Prices that expire at midnight are a pressure tactic, not a genuine offer. A good installer will be just as good — and will offer the same price — next week. Take your time, get other quotes, and only sign when you're fully satisfied.
Do I need an MCS-certified installer?
Yes, if you want to access the Smart Export Guarantee (SEG) — the government-backed scheme that pays you for surplus electricity exported to the grid. Without a valid MCS installation certificate, no licensed supplier is permitted to pay you export income. MCS certification also provides important consumer protections and is required by many home insurers for solar-equipped properties.
Is solar worth it if I won't be home during the day?
It's worth thinking about carefully. Solar generates electricity during daylight hours, and electricity you use directly from your panels is worth much more than what you export (you save the import rate you'd otherwise pay, which is currently higher than most SEG export rates). If you're out all day, you'll export a larger proportion, which earns less. A battery can help by storing generation for evening use — but it adds cost and extends the payback period. An honest installer will model both scenarios for your specific usage.