A solar quote that looks £1,500 cheaper than a rival's might actually cost you more — because it's quietly left out scaffolding, grid paperwork and the MCS certificate you'll need to get paid for your surplus electricity. This guide walks you through every line of a solar quote so you can compare them honestly, spot the gaps, and avoid a nasty surprise on install day.
Why solar quotes vary so much in price
You ask three local installers to quote on the same 4kW system. You get back three numbers that look nothing alike. This is one of the most common frustrations homeowners face — and it's almost never about one company being dishonest. It's usually about them not quoting the same thing.
The hardware — panels, inverter, mounting rails — is only part of what you're buying. Solar panel costs in the UK in 2026 vary by system size, roof type, panel tier, and crucially, what the installer has chosen to include or exclude from their quoted price. Two quotes for a nominally identical 4kW system can legitimately differ by £1,500–£2,500 based purely on inclusions.
Your job isn't to find the cheapest quote. It's to find the best value for a complete, properly installed system. That means you need to know what a complete quote should contain.
What every solar quote should include — line by line
A fully-priced quote from a reputable, MCS-certified installer should cover all of the following. If any of these items are missing, ask directly whether they're included in the price before you go any further.
- Panels — brand, model and wattage specified. Not just "10 x 400W panels". You want the manufacturer name and model number so you can check the warranty and performance independently. Tier-1 brands (such as JA Solar, LONGi, Jinko, Canadian Solar) are widely regarded as a safe mid-range choice for most homes.
- Inverter — type and model specified. String, micro or optimised — and the brand. The inverter converts your panels' DC output into usable AC electricity and is one of the components most likely to need attention over the system's lifetime. A generic "inverter included" line is not enough.
- Mounting hardware. Rails, roof hooks and clamps suited to your specific roof type. Slate roofs require different fixings from concrete tile — if your quote doesn't mention your roof type, that's a question to ask.
- All DC and AC electrical work. From the panels down to your consumer unit, including any isolators, surge protection and earthing. Vague wording like "all wiring" should be pressed for detail.
- Scaffolding. This is one of the most common hidden costs. Depending on how difficult it is to access your roof, scaffolding can add anywhere from £300 to over £1,000 to the total cost of a domestic installation. A bungalow with straightforward access may avoid it entirely; a three-storey terrace or steep pitch almost certainly won't. Always ask explicitly: is scaffolding included?
- DNO notification or application. Every grid-connected solar system in the UK requires contact with your Distribution Network Operator (DNO). For most standard domestic systems (inverters up to 3.68kW on a single-phase supply), this is a G98 notification submitted by your installer after the work is done — no waiting required. Larger systems or those with battery storage may need a G99 application submitted before installation, which can take several weeks to be approved. Either way, handling this is your installer's job, and it should be included in the price.
- MCS certification and paperwork. MCS (the Microgeneration Certification Scheme) is the UK's quality standard for small-scale renewable energy. Your MCS certificate is the document that proves your system was installed to a recognised standard — and you'll need it to register for Smart Export Guarantee (SEG) payments, to support manufacturer warranty claims, and to satisfy buyers if you ever sell your home. Without it, you can't get paid for the electricity you export to the grid. Reputable installers include MCS certification as standard; if it's listed as an extra, ask why.
- System monitoring. A basic monitoring app or display so you can see what your system is generating. Not all quotes include this — worth confirming.
- Warranties — product and workmanship. Panel performance warranties typically run 25 years; inverter warranties are commonly 5–12 years (extendable). Workmanship warranties cover the installation itself. These should be stated in writing, not just mentioned verbally.
The three things cheap quotes most often leave out
Based on what homeowners regularly report, three items account for most of the "nasty surprise" additions that appear after you've accepted a quote:
1. Scaffolding
It's not glamorous, but it's unavoidable on most two-storey homes. Some installers — particularly those quoting online from satellite images alone — will note scaffolding as "to be assessed" or leave it off entirely. If you've accepted a quote before the installer has visited, insist on a site survey before signing a contract. An in-person survey is the only way to give you a firm, all-inclusive price.
2. DNO notification or G99 application
DNO handling should be a standard inclusion from any MCS-certified installer — but it's not always listed. For larger systems or battery-inclusive quotes, a G99 pre-approval can take several weeks. If your installer hasn't flagged this and your system turns out to need it, your install date could slip significantly. Ask explicitly: "Does this price cover the G98 or G99 application, and have you checked which one applies to my system?"
3. MCS paperwork and registration
The MCS certificate is not an optional add-on — it's the document that unlocks SEG payments and satisfies future property buyers. Energy Saving Trust notes that suppliers may ask for an MCS certificate as proof that your installation meets the required standard. If an installer doesn't mention it in their quote, that's a red flag. You can check whether any installer holds current MCS certification at mcscertified.com before you invite them to quote.
How to compare quotes like-for-like
Once you have two or three itemised quotes in front of you, don't just look at the bottom line. Work through this process:
Check the system specification first. Are the quotes for the same system size (kWp)? The same number of panels? The same inverter type? A 4kW system using budget panels and a cheap string inverter is a different product from a 4kW system with premium monocrystalline panels and a hybrid inverter — even if the headline numbers look similar.
Look for what's not there. Go through the checklist above and mark anything that isn't explicitly mentioned. Then ask each installer to confirm in writing whether those items are included. A reputable installer won't mind the question.
Check VAT. Residential solar installations in the UK are currently zero-rated for VAT — 0% applies until at least March 2027, according to government policy. Make sure every quote you're comparing is VAT-inclusive at 0%. If one quote is quoted ex-VAT or at a different rate, you're not comparing the same number.
Ask about the expected annual output. A good installer will provide an estimated annual generation figure in kWh, based on your roof's orientation, pitch and location — not a generic national average. This matters because it's the basis of any savings estimate. Be cautious of quotes that don't include this, or that quote suspiciously high generation figures. Our guide to solar panel payback time in 2026 explains how to sanity-check these numbers.
Get at least three quotes. This isn't just about price — it's about getting a range of professional opinions on system design, sizing and what your roof actually needs. A single quote gives you no frame of reference.
When is a lower quote genuinely better value?
Not every cheaper quote is cutting corners. A lower price can be legitimate if the installer has lower overheads, uses a slightly less premium panel brand, or operates in an area with lower labour costs. What matters is whether the specification is comparable and the inclusions are the same.
A quote is a red flag if it refuses to itemise costs, if it can't name the panel and inverter brands, or if scaffolding and MCS paperwork are listed as extras "to be confirmed". For more on warning signs, see our guide to solar quote red flags.
It's also worth being honest with yourself about whether solar is the right move at all. If your roof is heavily shaded, north-facing, or in poor condition, the best quote in the world won't make the system financially worthwhile. A good installer will tell you this upfront. One who doesn't is worth walking away from.
One more thing: how FairSolar is paid
FairSolar is free to use as a homeowner. If you're curious about how the service works, you can read the full explanation at how FairSolar is paid. The short version: you never pay anything, and you're never obligated to accept a quote.
If you'd like to put this checklist to work with real quotes from vetted, MCS-certified installers local to you, you can get free, no-obligation quotes through FairSolar. Fill in a short form, and we'll connect you with installers who can give you a fully itemised price — no pushy sales calls, no obligation to proceed.
Frequently asked questions
What should a solar panel quote include in the UK?
A complete quote should specify the panel brand, model and wattage; inverter type and brand; mounting hardware; all DC and AC electrical work; scaffolding (where needed); DNO notification or G99 application; MCS certification and paperwork; system monitoring; and both product and workmanship warranties. If any of these are missing or listed as extras, ask the installer to confirm whether they're covered before you sign anything.
Why are solar panel quotes so different in price?
Two quotes for the same system size can differ by £1,500–£2,500 or more because they're not quoting the same thing. Differences in panel tier, inverter type, whether scaffolding is included, roof complexity, and whether MCS paperwork and DNO handling are bundled in all affect the final number. Always compare itemised quotes rather than headline totals.
Do I need an MCS certificate and why does it matter?
Yes — your MCS certificate is the document you need to register for Smart Export Guarantee (SEG) payments (so you get paid for electricity you export to the grid), to support manufacturer warranty claims, and to satisfy buyers if you sell your home. Without it, you lose access to export income and some consumer protections. Any reputable MCS-certified installer will include this as standard, not as an extra.
What is DNO notification and should it be included in my quote?
Your Distribution Network Operator (DNO) must be informed whenever a solar system is connected to the grid. For most standard domestic systems (inverters up to 3.68kW), this is a simple G98 notification your installer submits after installation at no extra cost. Larger systems may need a G99 application approved before installation, which can take several weeks. Either way, your installer should handle this and it should be included in the quoted price — not added on later.
How do I know if a solar quote is fair?
A fair quote names the panel brand, model and inverter explicitly; includes scaffolding, DNO handling and MCS certification without listing them as extras; and provides an estimated annual output in kWh based on your specific roof. Getting at least three itemised quotes from MCS-certified installers is the most reliable way to benchmark price and specification. If an installer won't itemise costs or can't name the equipment they're quoting, that's a warning sign.