Finding the right solar panel installer matters more than finding the cheapest one. You need an MCS-certified company to qualify for any government grant or Smart Export Guarantee payments. A good installer will survey your roof, design a system matched to your usage, handle the DNO notification, and register your installation with MCS, all for between £5,000 and £9,000 on a typical 4kW system.
Here's the problem. The solar market has grown fast and quality varies enormously. We see homeowners get three quotes where the cheapest is half the price of the most expensive, and they're left wondering who to trust. This guide covers exactly what to look for, what to ask, and what should send you running.
What Does a Solar Panel Installer Actually Do?
More than bolting panels to your roof.
Check if you qualify
Answer a few quick questions to see which government energy grants you're eligible for. Free, instant results.
A proper installation involves a site survey (checking roof orientation, shading, structural integrity, and your consumer unit), system design matched to your electricity usage patterns, scaffolding, the physical panel and inverter installation, wiring into your existing electrics, DNO notification to your local distribution network operator, and MCS registration. That last bit is what gives you the certificate you'll need for export payments and any grant applications.
The whole process from first survey to switched-on panels typically takes 4 to 8 weeks. The actual installation day? Usually just one day for a standard domestic system. Two if you're adding battery storage.
Here's what most guides won't tell you: the survey stage is where the real value lies. A good installer will spot things like a weak rafter that needs reinforcing, or recommend waiting six months until your south-facing extension is finished. A bad one just measures the roof and emails a quote. The difference between those two approaches can save you thousands down the line, or cost you thousands if you pick the wrong one.
How to Check If an Installer Is MCS Certified
Non-negotiable.
If your installer isn't MCS certified, you cannot claim Smart Export Guarantee payments, you cannot access ECO4 funding, and your installation won't meet the quality standards that protect you if something goes wrong.
Checking takes about thirty seconds. Go to mcscertified.com, enter your postcode, select "Solar PV" as the technology, and you'll see every certified installer in your area. The MCS database shows their certification number, what they're certified to install, and whether their certification is current.
Some things to note:
Certification is company-specific, not individual. The company holds the certificate, and their named operatives work under it.
A company can be MCS certified for solar PV but not for battery storage. Check they hold certification for everything they're quoting you.
Certification can lapse. Always check the database yourself rather than trusting a logo on their website.
About 3,000 MCS-certified solar installers are currently active in the UK, though that number shifts monthly as companies join and leave the scheme. Coverage is good in most of England and Wales, thinner in parts of Scotland and Northern Ireland.
Questions to Ask Before You Get a Quote
Right, so you've found three MCS-certified installers in your area. Now what?
Don't just ask "how much?" The quote price matters, obviously, but the questions below will tell you far more about whether this company is worth your money.
Ask them what panels and inverter they'd recommend for your roof and why. A good installer will name specific brands and explain the trade-off between cost and performance. If they just say "Tier 1 panels" without naming a manufacturer, push back. Tier 1 is a bankability rating from Bloomberg — it means banks will lend against projects using those panels. It's not a quality guarantee. Not even close.
Ask about their workmanship warranty versus the manufacturer's product warranty. You want at least 10 years from the installer on their labour and at least 25 years from the panel manufacturer on output. These are separate things and some companies blur the distinction deliberately.
Who handles the DNO application? This should be included. If they tell you to do it yourself, that's unusual for a domestic installation and honestly a bit of a red flag.
And ask what happens if your roof needs work in five years. Can the panels be removed and refitted? What would that cost? Some installers offer this as part of an ongoing maintenance agreement. Others charge separately.
One question people forget: ask how they'll handle your consumer unit. If your fuse board is old and doesn't have space for an additional circuit breaker, the installer may need to upgrade it. £200 to £400. That should appear on the quote, not as a surprise on installation day.
How Much Should Solar Panel Installation Cost in 2026?
£6,500. That's roughly the average for a 4kW system on a standard roof in England, based on current MCS data and the quotes we see come through.
But "average" hides a lot of variation:
Factor
Impact on cost
System size (3kW vs 5kW)
£4,500 to £9,000+
Panel brand (budget vs premium)
±£500 to £1,000
Inverter type (string vs micro)
Micro-inverters add £500 to £800
Scaffolding complexity
Standard is included, complex roofs add £300 to £600
Consumer unit upgrade
£200 to £400 if needed
Battery addition
£2,500 to £5,000 on top
Location (London vs North East)
London typically 10-15% higher
We've covered the full breakdown in our solar panel costs guide, but the key point here is: get three quotes minimum and compare like-for-like. Make sure each quote specifies the same panel wattage, same inverter type, and same warranty terms before you compare prices.
Under £4,000 for a 4kW system? Be suspicious. Either the panels are very low quality, the warranty is minimal, or something is being left out of the quote.
Can You Get a Grant to Help Cover the Cost?
Two schemes can help right now, though they work very differently.
ECO4 is the big one. If your household receives qualifying benefits (Universal Credit, Pension Credit, Child Tax Credit, and others) and your home has an EPC rating of D or below, ECO4 can fund solar panel installation in full. No contribution from you. The catch is that solar is only funded where it's part of a broader package of energy efficiency measures, and your installer needs to be working with an ECO-obligated energy supplier. The scheme runs until December 2026, so there's still time but the window is narrowing. We've written a full guide to solar panel grants covering eligibility in detail.
The Warm Homes: Local Grant works differently — administered by your local authority, amounts vary by area, targets low-income households in poorly insulated homes. Solar isn't always included but some councils do fund it as part of a package. Check our Warm Homes guide for how to find your local scheme.
Everyone else gets 0% VAT on domestic solar installations. That saves roughly £1,000 to £1,500 compared to the old 20% rate. No forms. No income test. Just a lower invoice. Your installer should apply this automatically — if they charge you VAT on a domestic solar installation in 2026, challenge it immediately.
And once your panels are generating, you'll earn export payments through the Smart Export Guarantee. Octopus Energy currently pays around 15p per kWh exported. British Gas sits around 12p. Some smaller suppliers offer as little as 3p. But you only qualify if your installation was done by an MCS-certified installer. Full circle.
Red Flags When Choosing a Solar Panel Installer
So. Here's where we get opinionated.
The solar industry has a quality problem. Not a massive one, but enough that you need to know what to avoid.
Door-to-door sales. Any company that knocks on your door uninvited and offers solar panels is not worth your time. This is the single most common route to a bad installation — the sales pressure, the "today only" pricing, the inflated finance agreements. Walk away. Always. We've never seen a good outcome from a doorstep solar sale. Not once.
No site survey before quoting. If someone quotes you a fixed price based on a Google Earth screenshot of your roof, they haven't checked your rafters, your shading, your consumer unit, or your actual electricity usage. A quote without a physical survey (or at minimum a detailed video call survey) isn't a real quote. It's a guess with a price tag.
Pressure to sign finance agreements on the spot. Solar finance can make sense for some people, but it should never be a condition of the quote. If an installer won't give you a cash price and only talks in "monthly payments," they're selling finance, not solar panels.
Vague warranty terms. "25-year warranty" means nothing without knowing what's covered. Panel degradation warranty, product warranty, and installer workmanship warranty are three different things. If they can't clearly separate them, move on.
No MCS number on the quote. Should appear on every document they give you. No number, no certification, no deal.
Honestly, the simplest test is this: does the company answer your questions directly, or do they redirect into a sales pitch? Good installers are happy to explain technical details because they know their work stands up to scrutiny.
One more thing worth mentioning, slightly tangentially: we've noticed that companies offering solar panel cleaning packages bundled with installation tend to be more established operations with ongoing customer relationships. It's not a guarantee of quality, but it suggests they expect to see you again. Anyway.
If you want to check whether you qualify for funded installation through ECO4 or the Warm Homes scheme, open our eligibility checker. Two minutes. You'll know exactly where you stand.
This article contains affiliate links. If you request quotes through our links, we may receive a commission at no extra cost to you. This helps keep Eco Home Check free and independent. How we earn
Grant amounts and eligibility criteria are based on publicly available government data and may change. Always verify current terms directly with the scheme provider.
Frequently asked questions
How long does a solar panel installation take?
One day for a standard 4kW domestic system. Adding battery storage or dealing with a complex roof (multiple orientations, dormers, flat roof mounting) might stretch it to two. The overall process from first enquiry to generation takes 4 to 8 weeks, but most of that is survey scheduling, design, scaffolding booking, and DNO notification rather than physical work on your roof.
Do I need planning permission for solar panels?
Usually not. Solar panels on domestic roofs fall under permitted development rights in England and Wales, provided they don't protrude more than 200mm from the roof surface and aren't on a listed building or in a conservation area. Your installer should confirm this during the survey. If you're in Scotland, the rules are similar but check your local authority to be safe.
Can I install solar panels myself?
Technically yes. But you'd lose access to the Smart Export Guarantee, any grant funding, and your installation wouldn't be MCS registered. The electrical connection to your consumer unit must be done by a Part P qualified electrician regardless. For most homeowners, self-installation creates more problems than it solves — and the savings are smaller than you'd think once you factor in scaffolding hire and the lost SEG income.
What happens if my installer goes bust?
Your panel manufacturer warranty still stands — that's between you and the manufacturer directly. But the installer's workmanship warranty dies with the company. This is why we recommend choosing established companies with at least 5 years of trading history. Check Companies House for their incorporation date and financial filings. Some installers also offer insurance-backed guarantees through third parties like HIES or RECC, which survive even if the company folds.
How many quotes should I get?
Three minimum. Five if you have the patience. The spread between cheapest and most expensive will tell you a lot about what's realistic for your roof.