You’ve done the hard bit. You’ve decided to go solar, you’ve rung round, and now you’ve got two or three quotes sitting in your inbox. They’re all for what sounds like the same thing. The headline numbers are anywhere from £5,500 to £10,500. One installer says you need 12 panels, another says 14, a third throws in a 10kWh battery you didn’t ask for. So how do you actually work out how to compare solar panel quotes without picking the wrong one and regretting it five years from now?
That’s what this guide is for. We’ll walk through the line items, the credentials that matter, the warranty stack, and the questions to take back to each installer before signing. By the end you should be able to read a solar quote line by line and know which one is genuinely the best deal.
Get at least three quotes (and make them comparable)
Two quotes are barely better than one. There’s nothing to triangulate against, and the lower number always looks like the winner by default. Three is the sensible minimum. All three should be from MCS-certified installers (more on that in a moment), and broadly quoting on the same system size for the same roof.
If one installer comes back with a wildly different system size, say 3kWp when the other two are quoting 5kWp, don’t bin them straight away. Ask why. Sometimes the smaller system is the honest answer for a partially shaded roof. Sometimes the larger one is a numbers game to justify a battery. The point is to find out which.
What actually matters in a solar quote
Solar quotes have a habit of looking similar on the front page and very different once you start reading. Here are the line items that actually separate good from filler.
System size in kWp. This is the comparable number, not the panel count. A 4kWp system with 10 panels of 400W and a 4kWp system with 9 panels of 445W are the same system size, just packaged differently. Panel counts vary because wattages vary.
Panel brand and exact model. “Tier 1 panels” on a quote means almost nothing. Tier 1 is a financial bankability rating from BloombergNEF, not a quality rating. You want the exact panel model written down: the brand, the wattage, and ideally the series. JA Solar 445W DeepBlue 4.0 is a different beast from a generic 445W Chinese panel even if both technically meet the same spec.
Inverter brand and type. String, hybrid, or microinverter. Brand. Model number. Warranty length. If the inverter brand is missing from the quote entirely, that’s worth asking about, since this is the component most likely to be replaced in the system’s lifetime.
Battery brand and usable capacity (not nameplate). A 10kWh battery is rarely 10kWh of useful storage. We’ll come back to this.
Scaffolding. Real cost, sometimes inflated.
DNO application. This is the half-page paperwork your installer files with your Distribution Network Operator to let them know you’re connecting solar to the grid.
MCS certificate and SEG paperwork. Both should be included in the price.
Warranty stack. Panel product warranty, panel performance warranty, inverter warranty, battery warranty, workmanship warranty, and the insurance-backed guarantee. Not one number. Six.
If you haven’t yet read the broader case for going solar in the first place, our Are Solar Panels Worth It in the UK? guide covers the basic value proposition in more detail.
MCS, RECC, HIES: what credentials actually matter
There are three abbreviations that show up on most quotes, and they’re not the same thing.
MCS (Microgeneration Certification Scheme) is the one that matters most. Without it, you can’t register for the Smart Export Guarantee, which is how you get paid for exporting surplus electricity to the grid. No MCS certificate, no SEG income. That alone is a few hundred pounds a year of difference. A quote from an installer who isn’t MCS-certified is cheaper for a reason, and the reason is usually that you’re forfeiting the export income forever.
RECC (Renewable Energy Consumer Code) and HIES (Home Insulation and Energy Systems contractors scheme) are consumer codes. Every MCS-certified installer has to be a member of one or the other. They give you a formal complaints process, an independent dispute resolution route, and deposit protection.
Insurance-backed guarantee (IBG) is the bit people miss. The workmanship warranty your installer provides is only as good as the installer themselves. If they go under in year three, that warranty walks out of the door with them, unless it’s backed by a third-party insurer. The IBG is what keeps the workmanship cover alive even if the installer ceases trading. As recent events in the UK battery market have shown, manufacturers and installers can and do disappear.
For more detail on how MCS certification connects to the export side, the Best Solar Export Tariff guide goes deeper.
You can verify any installer’s MCS status directly on the MCS installer database at mcscertified.com, and check their Consumer Code membership on the RECC website or HIES equivalent. Both take about thirty seconds.
Reading the panel line
What you actually want to see on the panel line, in plain English:
A named manufacturer. The mainstream brands installed across UK homes in 2026 are JA Solar, Longi, Trina, Jinko, Aiko, REC, and at the premium end SunPower. Any of these is a credible choice. Aiko and Longi tend to lead on efficiency. JA Solar and Trina tend to win on value. SunPower and REC sit at the top end on warranty length and degradation, with prices to match. There’s no single best panel for every roof.
Wattage. Mainstream UK residential modules in 2026 sit somewhere between 420W and 470W, with the premium back-contact panels pushing closer to 485W in the same footprint. Higher wattage matters if your roof space is tight. If you’ve got a large unshaded south-facing roof, you can fit more standard panels and get to the same total kWp for less money.
The warranty terms. Specifically, both warranties. A panel typically has a product warranty (the manufacturer fixes physical defects) and a performance warranty (the panel guarantees a certain percentage of output after a certain number of years). Product warranties in 2026 vary widely. JA Solar and Longi commonly sit around 15 years on product. Aiko offers up to 25 years. SunPower goes as far as 40. Performance warranties typically run 25 to 30 years and guarantee somewhere in the region of 87% to 92% of original output at the end of the period.
The brand badge matters less than the warranty terms and the installer’s willingness to honour them. A long warranty from a manufacturer who’s gone out of business is worth nothing.
Reading the inverter line
This is where quotes start to diverge.
String inverter. The simplest type. All panels run in a series string into a single inverter that converts DC to AC. Cheapest option, and fine for a simple unshaded south-facing roof. The downside: if one panel is shaded, the whole string drops to that level of output.
Hybrid inverter. A string inverter with a battery interface built in. This is the default for most new installs that include a battery or that might add one later. GivEnergy, Fox ESS, Sunsynk, Solis, SolaX, and SolarEdge all make hybrid inverters used widely in UK homes.
Microinverters or DC optimisers. Enphase microinverters and SolarEdge optimisers do panel-level conversion or optimisation. Each panel works independently, so shade on one doesn’t drop the others. Real value on complex or shaded roofs. Overkill on a simple roof, and pricier.
Inverter warranties are typically 10 to 12 years, sometimes extendable to 20. That’s a lot shorter than your panels’ 25-year-plus performance warranty. In practice, the inverter is the component most likely to be replaced during the system’s lifetime, and a year-15 replacement is a realistic cost to factor in.
A note on GivEnergy. In April 2026, GivEnergy Ltd entered administration. The company has ceased trading, no further manufacturer warranties are being honoured directly by GivEnergy Ltd, and direct technical support has stopped. The hardware itself continues to work, and the cloud platform is run by a separate group company that is not in administration. But anyone being quoted a GivEnergy inverter or battery in 2026 should ask the installer pointedly: what happens to my warranty? Some installers are offering their own extended workmanship cover to bridge the gap. Others are quietly switching to alternatives like Fox ESS, Sunsynk, or SolaX. This is a live situation and worth checking before signing anything.
Reading the battery line (if quoted)
The big one. Three things to look at.
Usable vs nameplate capacity. A battery marketed as “10kWh” rarely delivers 10kWh of usable energy. The depth of discharge limit, the round-trip efficiency, and the manufacturer’s reserve all eat into the headline number. The honest figure to ask for is usable capacity, sometimes shown on datasheets as “usable energy” or “discharge capacity”. Often around 90 to 95% of nameplate.
Cycle warranty. Batteries are warranted by cycles or years, whichever comes first. A typical residential battery in 2026 comes with a 10-year warranty or a cycle count somewhere in the region of 6,000 to 10,000 full cycles. One cycle a day for ten years works out at 3,650 cycles, so most homes will hit the time limit before the cycle limit.
Round-trip efficiency. The percentage of energy you get back out for every kWh you put in. Most modern batteries are around 90 to 95%. The remaining 5 to 10% is lost as heat.
Honest point. A battery only pays back if your household actually uses the stored energy in the evening. If you’re at work all day and at home from 6pm, a battery helps you self-consume the solar you generated while you were out. If you’re at home all day and run most of your appliances when the sun’s up, the battery sees less action and the payback stretches out. Oversizing the battery is one of the most common quote-padding moves. A 10kWh battery on a household that uses 8kWh a day is doing very little extra work for a lot of extra money. Match the battery to your usage, not to the installer’s preferred upsell.
For a deeper look at sizing and brand selection, see our Best Home Batteries for Solar guide.
Reading the generation estimate
Every MCS-certified installer produces an annual generation estimate in kWh, calculated using the standardised methodology in MCS MIS 3002. The methodology accounts for your postcode’s solar irradiance (the Kk value), your roof pitch, orientation, and a shading factor. Different installers using the same methodology on the same roof should produce numbers within roughly 10% of each other.
If one installer’s generation estimate is 30% above the other two, that’s usually not better panels. It’s an optimistic shading factor or a different orientation assumption. This is one of the easiest places to spot a quote that’s been written to win the sale rather than reflect reality. Ask each installer for the Kk value they’ve used and the shading factor they’ve applied. If they can’t tell you, that’s the answer.
Scaffolding, DNO, and the “extras” line
Scaffolding is a real cost. For most UK homes in 2026 it’s somewhere in the region of £600 to £1,200 depending on the height of your roof, access, and how many lifts the scaffolders need to put up. It’s also one of the easiest line items for an installer to inflate, particularly when it’s bundled into a “fixed price” rather than itemised.
DNO application is the form your installer submits to your local Distribution Network Operator to register the system. For a typical sub-3.68kW single-phase install this is a G98 notification, submitted within 28 days of commissioning. For larger systems, it’s a G99 application made before installation. The form itself is free for the installer to submit. If a quote shows £300 for “DNO application”, ask what’s involved.
Bird protection mesh, mid-clamps, optimisers retrofitted later, “system commissioning” charges, app subscriptions. These are sometimes genuine line items and sometimes filler. The rule of thumb: any line your installer can’t explain in one sentence is worth pushing back on.
Comparing the warranty stack
A “25-year warranty” on a solar quote is almost never one number. It’s a stack of six.
| Warranty layer | Typical 2026 range |
|---|---|
| Panel product warranty | 15 to 25 years (40 years on premium SunPower) |
| Panel performance warranty | 25 to 30 years (guaranteeing 87% to 92% output) |
| Inverter warranty | 10 to 12 years, sometimes extendable |
| Battery warranty (if included) | 10 years or 6,000 to 10,000 cycles |
| Workmanship warranty (installer) | 2 to 25 years, varies wildly |
| Insurance-backed guarantee | Covers workmanship if installer ceases trading |
When you see “25-year warranty” plastered on the front page of a quote, that’s almost always the panel performance warranty alone. The inverter is on 10. The workmanship might be on 2. The IBG may or may not be there. Read each layer.
Spotting quote-padding tactics
A few things to keep an eye out for, written out plainly:
- Oversized batteries on small households. If your daily usage is 7kWh and you’ve been quoted 13kWh of battery storage, ask why.
- Premium microinverters on a south-facing unshaded roof. Microinverters and DC optimisers earn their premium on complex or shaded roofs. On a simple roof, they’re paying for something you don’t need.
- “Free” EV charger or smart meter integration baked into a higher headline. Sometimes these are genuinely included at little cost. Sometimes the quote is £1,500 above the next installer and the “free” extras explain the gap.
- Scaffolding charges that don’t match the access. A flat-fronted semi with easy garden access shouldn’t carry the same scaffolding bill as a three-storey terrace on a tight street.
- Vague “system commissioning” charges. Commissioning is part of the job. A separate line for it is sometimes legitimate, sometimes filler.
Not every line item that looks padded actually is. Ask, don’t assume.
The questions to ask before you sign
Take this list back to each installer.
- Is the MCS certificate issued in your company name, or are you subcontracting to a different MCS-certified installer?
- Which exact panel and inverter models are being installed? Model number, not just brand.
- What’s the usable battery capacity, not the nameplate?
- What’s the workmanship warranty length, and is it insurance-backed?
- What’s the annual generation estimate based on, and what shading factor did you apply?
- Is the price fixed, or subject to survey? If subject to survey, what can the survey change?
- When does the quote expire, and is the price held if VAT rules change before install?
The answers tell you a lot, and not always in what’s said. An installer who answers all seven without hesitation is a different animal from one who needs to “get back to you” on most of them.
Zero-rated VAT and what it means for the quote
Residential solar installations in the UK are zero-rated for VAT until 31 March 2027. From 1 April 2027, the rate is currently scheduled to revert to 5% for qualifying installations. This applies to the supply and installation of panels, batteries (including standalone battery storage retrofits), and the labour to fit them, provided the same provider supplies and installs the system.
Some quotes show 0% VAT as a separate line. Others bake it into the headline. Either is fine. What’s not fine is a quote that shows 5% or 20% VAT on a domestic install. That’s wrong and worth questioning. For more on the current VAT position and the published end date, the House of Commons Library briefing on VAT and energy-saving materials is the most authoritative source.
The ECO4 question: is there a grant?
For most homeowners reading this, no.
The ECO4 scheme, which provided fully funded or heavily subsidised solar installations for low-income households on qualifying benefits, has been extended to run until 31 December 2026. To qualify, you typically need an EPC rating of D to G, a household income broadly below £31,000, or receipt of certain means-tested benefits. If that’s you, applying through an ECO4-registered installer is genuinely worth doing.
For everyone else, the headline price on the quote is broadly what you’ll pay, minus the zero-rated VAT advantage that’s already in the price. The Warm Homes: Local Grant has replaced earlier schemes in some local authority areas with similar eligibility criteria and up to £15,000 available for qualifying low-income households. The broader £15 billion Warm Homes Plan is scheduled to launch from 2027 and is expected to fund solar PV, batteries, heat pumps, and insulation for a wider group, but the details are still being worked out and it doesn’t help with a quote you’re comparing today.
There’s no general solar grant for owner-occupier homeowners in 2026.
Summary comparison checklist
Lay your three quotes out side by side and fill this in. The columns force you to compare like for like, and the price-per-kWp row is the one that tells you most.
| Item | Quote 1 | Quote 2 | Quote 3 |
|---|---|---|---|
| System size (kWp) | |||
| Number of panels | |||
| Panel brand and wattage | |||
| Inverter brand and type | |||
| Battery brand | |||
| Battery usable capacity (kWh) | |||
| Annual generation estimate (kWh) | |||
| MCS-certified (yes/no) | |||
| RECC or HIES member (yes/no) | |||
| Insurance-backed guarantee (yes/no) | |||
| Workmanship warranty length | |||
| Total price including VAT | |||
| Price per kWp (total ÷ kWp) |
What it actually costs (rough 2026 ranges)
Useful 2026 benchmarks for a standard UK home, fully installed including 0% VAT, panels, inverter, mounting, scaffolding, electrical work, DNO notification and MCS certification:
- 3kWp system, no battery: roughly £4,000 to £5,500
- 4kWp system, no battery: roughly £5,000 to £7,500
- 6kWp system, no battery: roughly £7,000 to £9,000
- 4kWp system with a ~5kWh battery: roughly £8,000 to £12,000
- Larger systems with bigger batteries: £13,000 to £15,000+
In price-per-kWp terms, MCS installation data suggests the median for a domestic system in England in early 2026 was around £1,565 per kWp, with the national average closer to £1,800 to £1,900 per kWp. A quote substantially above £2,200 per kWp on a straightforward install is worth questioning. A quote substantially below £1,400 per kWp is worth questioning differently: ask about panel brand, warranty terms, and whether MCS certification is genuinely included.
Battery add-on rule of thumb: a 5kWh battery typically adds £2,000 to £3,000 to the install when fitted at the same time as the panels. A 10kWh battery typically adds £4,000 to £6,000. Retrofitting later costs more because the electrical work isn’t shared.
Step-by-step: working through your quotes
- Lay the three quotes out side by side and fill in the comparison checklist above. This single exercise sorts out 80% of the noise. You’ll often see one quote pull ahead just from this step.
- Check each installer’s MCS, RECC/HIES, and IBG status. MCS database takes thirty seconds. The Consumer Code page on the installer’s own website should name RECC or HIES with a membership number you can verify. Ask explicitly about the insurance-backed guarantee. Some installers offer it as standard, some only on request.
- Compare the generation estimates. Anything more than 10% above the others is a flag. Ask the high-estimate installer for the Kk value and shading factor.
- Compare price per kWp, not just headline price. A £6,800 4kWp install is £1,700 per kWp. A £9,500 5.5kWp install is £1,727 per kWp. Almost identical value, very different sticker. The headline tells you less than the unit cost.
- Compare the warranty stack layer by layer. Don’t accept “25 years” as the whole answer. Six numbers. Six warranties.
- Send the questions list back to each installer. Read the replies. Speed of response and clarity matter at least as much as the content.
- Pick on overall value, not lowest price. The cheapest quote is sometimes the right answer. Sometimes it’s the worst one. The checklist tells you which.
Common pitfalls
Picking purely on price. The headline number is the least informative figure on the page.
Picking purely on warranty length without reading the layers. “25 years” can hide a 2-year workmanship cover.
Accepting an oversized battery because the installer “recommends it”. Battery sizing should follow your evening usage pattern, not their preferred margin.
Not checking whether the MCS certificate will be issued in the installing company’s name. Some sales operations subcontract the actual install to an MCS-certified third party. That’s not automatically a problem, but you want to know about it.
Signing a quote that’s “subject to survey” without understanding what the survey can change. If the survey can re-quote scaffolding, that’s fair. If it can re-quote the panels or system size, the original quote was never really a quote.
Missing that the inverter brand isn’t named on the quote at all. Surprisingly common. Push back.
Special cases
Complex or shaded roofs. Microinverters (Enphase) or DC optimisers (SolarEdge) genuinely earn their premium here. The optimiser premium adds roughly £40 to £80 per panel installed, but on a roof where one chimney shadow drops a whole string’s output, it pays back through generation.
Listed buildings and conservation areas. Solar panels are permitted development for most UK homes, provided the panels don’t project more than 200mm from the roof surface, the building isn’t listed, and you’re not in a designated area. If your home is listed or in a conservation area, you’ll need planning permission, and the installer should flag this. The Permitted Development Rights guidance on GOV.UK is the official position.
Households on Octopus Go, Cosy Octopus, or planning a switch. Battery economics shift if you can charge from the grid at off-peak rates. A battery that wouldn’t pay back on solar alone often does on a smart tariff. Worth modelling. See the Best EV Tariffs UK guide if you’re moving toward electrification.
Households planning a heat pump within the next 2 to 3 years. Size the solar system with that future load in mind. Going from a 4kWp panel array to a 6kWp array at install is much cheaper than adding panels later.
Households planning to move within 5 years. Be honest with yourself about whether the system fully pays back in that window. Solar can add to a sale price, but not pound for pound. If you’re 80% sure you’re moving in three years, the economics are different from a 20-year hold.
Park homes and flats. Different rules on permitted development and ownership. Worth flagging to the installer upfront.
FAQ
How many solar quotes should I get?
Three minimum. Two is enough to feel like you’ve compared, not enough to actually triangulate. With three you can spot the outlier.
What’s MCS certification and why does it matter?
The Microgeneration Certification Scheme is the UK quality assurance standard for small-scale renewable installations. The certificate matters because without it, you can’t register for the Smart Export Guarantee and get paid for exported electricity. It’s also required by most home insurers and by mortgage lenders when you sell.
Is a longer warranty always better?
Only if you read all six layers. A 25-year performance warranty paired with a 2-year workmanship warranty is a very different thing from a 25-year performance warranty paired with a 10-year insurance-backed workmanship warranty.
How do I know if a battery is the right size?
Look at your evening electricity use, roughly from 5pm to 11pm. That’s the consumption a battery actually replaces. If you use about 4kWh in that window in summer and 6kWh in winter, a battery somewhere in the 5 to 7kWh range will cover most of it. Bigger isn’t better. Bigger is just more expensive.
What does kWp actually mean?
Kilowatt-peak. The maximum power output of your panel array under standard test conditions. A 4kWp system on a south-facing UK roof typically generates around 3,400 to 3,800 kWh per year, depending on location and pitch.
Are cheap solar panels worth it?
Sometimes. The cheapest Tier 1 panel from a credible installer is often the best value choice. The cheapest panel from an installer with no Consumer Code membership, no IBG, and no MCS certificate is almost never worth it.
What’s an insurance-backed guarantee?
A third-party insurance policy that keeps your workmanship warranty alive if your installer goes out of business. Essential. Ask explicitly for it.
Do I need planning permission for solar panels?
For most homes, no. Roof-mounted solar is permitted development provided the panels don’t protrude more than 200mm from the roof surface and the property isn’t listed or in a designated area. Ground-mounted systems are a different matter.
In short
The headline price on a solar quote tells you less than three other things: the price per kWp, the warranty stack, and the credentials behind the installer. Get three quotes. Fill in the checklist. Push back on the line items that don’t make sense. Pick the one that gives you the best overall value, not the lowest sticker.
If you’re now thinking about the returns side of the equation, our Are Solar Panels Worth It in the UK? and Best Solar Export Tariff guides pick up where this one leaves off.
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