For many homeowners, an important part of the decision to get solar panels is working out who to trust with the installation.
This is partly because many quotes look similar at first glance. Two installers might offer a system with the same number of panels and a battery of a similar size, yet the real differences can be buried in the details. Key factors to consider are how well the system has been designed for your home and whether savings estimates are realistic. It's also worthing thinking about what warranties are actually included, and what support you will get if something goes wrong years later.
That's why choosing a solar panel installer requires more than just comparing prices. You also need to work out whether the company in question understands your home, can justify its recommendations, and will still be useful once the scaffolding has come down.
Get a quote for solar panels for your home
Use our comparison tool to get free quotes from leading solar panel installers.
Start with accreditation and credibility
The first checks are the simplest, but they matter. Before anything else, make sure the installer is accredited through a recognised scheme such as MCS or Flexi-Orb. If an installer is not properly certified, that should be a major red flag. Ed Janvrin, director of franchise at OVO, explains: “If the installer isn’t MCS certified, the customer won’t be eligible to sign up for the Smart Export Guarantee (SEG).”
Accreditation alone is not enough, though. Alfie Ireland, head of operations at Sunsave, says it is also worth looking closely at customer reviews and the company’s broader track record. Buyers should ask whether the solar installer has strong credibility, including a high Trustpilot score, and whether it is likely to still be around in 10 years’ time if support is needed.
A solar panel system should last you decades, so if an installer disappears after a couple of years, any promise of support or workmanship cover may disappear with it.
Look carefully at how they quote and survey your home
A good installer should not give you a meaningful quote without first understanding the property.
That does not always mean an in-person visit at the start. Many installers now begin with a remote assessment using satellite imagery, digital design tools and photos supplied by the customer. Janvrin says OVO’s process starts with a consultation of around 10 to 30 minutes, followed by a virtual survey using software to assess the roof, loft, electricity meter and scaffolding access. Ireland also says installers increasingly assess homes remotely before providing a tailored quote and savings estimate.
What matters is not whether the first survey is virtual or physical, but whether it is thorough. A proper assessment should examine factors such as roof condition, usable roof space, pitch, orientation, shading, tile type, scaffolding complexity and the likely route for wiring.
Most importantly, a good installer should be prepared to tell you when your home is not suitable for solar. Janvrin says that is one of the key functions of the survey process: confirming whether the property will genuinely benefit. “Not every home will benefit from it, and we’d rather inform a customer up front,” he says. That may not be what a customer wants to hear, but it is a far better outcome than being sold a poor-fit system.
If the installer proceeds to the next stage, there may also be a more detailed technical survey. Janvrin says OVO carries out a free in-person survey after quote acceptance to check for safety hazards and confirm the practical realities on site. Ireland adds that customers may also be asked to send photos of areas such as the loft, electricity meter and preferred battery location before an installation goes ahead.
Check whether the system has actually been designed for your home
A good quote should show that the solar panel system has been designed around the property and your energy use.
That starts with the number of panels. Janvrin says OVO sizes systems by looking at annual energy consumption, site-specific solar yield and roof safety requirements, while aiming to cover at least 50 per cent of the household’s electricity needs. Meanwhile, Ireland adds that a good design makes full use of all suitable roof space within safety guidelines, arguing that if a home can only fit around six panels, it is rarely worth going ahead.
The inverter choice should also be justified. Ireland says most installations perform well with a standard string inverter, and that microinverters are usually only necessary where there is significant unavoidable shading.
The same applies to batteries. Janvrin says the right battery size depends on the number of panels and the household’s energy use. A useful question for buyers to ask directly is: why has an installer chosen a specific size, and how does it relate to usage pattern? A battery recommendation should be rooted in your likely surplus generation and when you actually use electricity, not in a generic upsell.
Know the most common ways people get oversold
Solar is a mature technology, but that does not mean every quote is as straightforward as it looks.
According to Ireland, one of the most common ways people get oversold is being told they need microinverters or optimisers. These can be helpful in specific cases, particularly where shading is a serious issue, but they significantly increase the total cost of a system and are often unnecessary. He argues that many shading-related problems can instead be addressed through better system design, such as placing panels on different strings.
Janvrin points to another common oversell: battery sizing without a clear rationale. If an installer cannot explain why a battery of a certain capacity suits your home, that should raise questions. Bigger is not always better if the system is not properly matched to your generation and usage.
Savings projections also deserve scrutiny. Buyers should ask how the installer has calculated the expected savings, what assumptions sit behind those figures, and whether those assumptions are realistic for the way the household actually uses electricity.
The goal here is not to assume every installer is exaggerating, but to simply make sure your quote is based on design logic rather than sales logic.
Pay attention to what is missing from the quote
Underselling can be just as much of a problem as overselling. Ireland says one of the most common omissions is bird protection. This relatively modest add-on helps stop pigeons nesting under solar panels, which can otherwise lead to mess, noise, reduced output and even safety issues. Leaving it out may make the quote look cheaper, but adding it later is far more expensive because scaffolding may need to go back up.
Warranties are another area where important details can get glossed over. Janvrin warns that some installers highlight cover for panels and inverters but say little about wiring, fixings and fittings. Buyers should make sure they understand what is covered across the entire system, not just the components that are easiest to market.
It's also worth checking whether the installer is handling the paperwork that sits behind the installation. Ireland says that if an inverter larger than 3.68kW is being installed, the home will usually need permission from the Distribution Network Operator through a G99 application before it can connect to the grid. Any competent installer should manage that process for the customer.
Understand which warranties actually matter
Solar quotes often feature impressive-looking warranty language, but it's important to understand the difference between product cover and meaningful support.
With solar panel systems, there are several layers of warranty. There may be product warranties on panels, inverters and batteries; performance warranties on panels and batteries; and a workmanship warranty from the installer. In theory, that sounds reassuring.
In practice, the picture is more mixed. Ireland notes that workmanship warranties are often only two to five years, which is short compared with the 30- to 40-year lifespan of a typical solar panel system. He also points out that batteries and inverters may need replacing well before the panels do, and that many homeowners will struggle to judge for themselves whether a product is underperforming against its warranty terms.
This is why aftercare matters so much. Ireland argues that long-term maintenance support is at least as important as the warranties themselves, because otherwise the homeowner may be left to navigate faults, replacement parts and warranty claims alone.
Janvrin puts more emphasis on the value of a stronger workmanship promise, noting that OVO offers a 10-year workmanship warranty alongside standard 25-year panel performance warranties. Whether or not an installer offers cover on that scale, a key question for buyers is who will actually help if something fails years later?
Ask what happens after installation
It's easy to focus on survey day and install day, but a good installer should also be able to explain what happens afterwards.
Janvrin says that once installation is complete, OVO’s installer helps the customer set up a monitoring app so they can track generation in real time, and leaves a handover pack including the MCS certificate so they are ready to sign up for the Smart Export Guarantee. Ireland says most homes will also receive access to an app from either the installer or inverter manufacturer that shows what the system is generating, storing and exporting.
That monitoring is useful, but it is not the same as ongoing support. Ireland argues that many homeowners will not know whether a subtle drop in output is normal or a sign that something is wrong. For that reason, it says installer monitoring and long-term maintenance support can be one of the most valuable parts of the package.
This is one of the clearest ways to distinguish between a company that is focused on getting the install done and one that is prepared to support the system over time.
The questions to ask before you pay a deposit
By the time you are choosing between quotes for solar panels, a short list of questions can tell you a lot.
- Are you accredited by MCS or Flexi-Orb?
- How was my savings estimate calculated?
- Why have you recommended this specific number of panels, this inverter and this battery size?
- Which warranties are included, and who honours them?
- What happens if a fault appears several years down the line?
- Does the quote include bird protection?
- Who handles DNO applications and other paperwork?
- What monitoring will I get, and will anyone help me interpret the data?
A strong installer should be able to answer all of those questions clearly and without becoming defensive.
The cheapest quote is not always the best value
The main thing to remember when buying solar panels is that choosing solely on price can be a mistake.
A low quote may reflect thinner support, weaker warranties, missing extras, poor system design or lower-quality equipment. That doesn't mean the most expensive option is automatically the best either. But if one installer is dramatically cheaper than the rest, it is worth finding out exactly what has been left out, simplified or assumed away.
With solar, the goal is not just to get panels on the roof. It is to end up with a system that performs well, is properly supported, and continues to deliver value over the long term.
7 things no one tells you before installing solar panels
Heat pumps explained: how they work and what they cost
Are solar panels worth it in the UK? An expert guide on how they work for your home
Best solar panel installers UK: Top-rated fitters for 2026, trusted by our experts
What really happens to solar panels when they stop working efficiently
Do heat pumps work in large or old homes? Homeowners give their verdict
Are Octopus solar panels really worth it? Here’s our expert’s verdict
