A solar quote can look simple at first: panels, inverter, battery, installation price. But the expensive problems usually hide in the details.
Before you compare quotes by headline price, check what each installer has actually included, what they have assumed, and what responsibility they are willing to put in writing.
For context, Energy Saving Trust says an average domestic solar panel system is around 3.5kWp and costs around £6,100 to install. When the overall decision can run into thousands of pounds, small differences in quote wording, battery assumptions or warranty cover can matter.
Solar quote checklist
| Quote area | What to check | Why it matters |
|---|---|---|
| System size | Total kWp, panel count and panel wattage | A cheaper quote may simply be a smaller system. |
| Panels | Brand, model, product warranty and performance warranty | “25-year warranty” can mean different things. |
| Inverter | Make, model, capacity and warranty length | Inverters often have shorter warranties than panels. |
| Battery | Usable capacity, separate price, warranty and cycle terms | A battery can help, but it should not be bundled without explanation. |
| Scaffolding | Whether it is included in the quoted price | Missing scaffolding costs can change the real total. |
| Electrical work | Consumer unit, isolator, cabling and monitoring assumptions | Some homes need extra work before installation. |
| Roof assumptions | Orientation, shading, roof condition and access | Output estimates depend heavily on site conditions. |
| MCS certification | Whether the installer and installation will be MCS-certified | MCS certification is often important for consumer protection and export payments. |
| DNO notification or application | Who handles DNO notification under G98, or a G99 application where required | Smaller systems may follow a fit-and-notify route, while larger systems may need approval before connection. |
| SEG/export | Whether export payments are explained separately | SEG rates and terms vary by supplier. |
| Workmanship warranty | What is covered, for how long, and by whom | Product warranties do not always cover installation workmanship. |
| Aftercare | Named contact route after installation | You need to know who helps if something stops working. |
| Deposit terms | Deposit amount, cancellation terms and change rules | Pressure around deposits is a warning sign. |
1. Do not compare headline prices too quickly
Two quotes can look similar while offering very different systems. One may include a larger array, better inverter, scaffolding, battery installation and clearer aftercare. Another may show a lower price but leave important costs or assumptions unclear.
Before deciding which quote is “cheaper”, compare the actual specification line by line. If one quote is much cheaper than the others, do not assume it is better value until you know exactly what has been left out.
2. Check the battery separately
A battery should be priced and explained separately from the solar panel system. If the installer recommends one, they should explain why it fits your usage pattern.
A battery may make more sense if you use more electricity in the evening, have a suitable time-of-use tariff, or want to store more solar generation for later. It may make less sense if you are often at home during the day and already use much of your solar electricity directly.
3. Ask about MCS, DNO and SEG
This is where many homeowners get lost, so the quote should be clear.
Energy Saving Trust recommends getting quotes from at least three MCS-certified installers. It also explains that a solar PV system must be registered or notified to the local Distribution Network Operator, and that the installer will usually do this for you.
The exact DNO process can depend on system size. Smaller microgeneration systems may fall under G98, where the installation is notified after commissioning. Larger systems may need a G99 application before connection. You do not need to become an expert in the paperwork, but you should ask the installer which route applies and who is responsible for handling it.
For export payments, Ofgem explains that Smart Export Guarantee licensees set the rate, contract length and other terms. That means export income should be treated as tariff-dependent, not as one fixed number that every supplier pays.
4. Break warranties into categories
A solar quote may use a large warranty number to sound reassuring. But “25 years” can refer to panel performance, not necessarily product faults, workmanship, inverter cover or battery cover.
Separate the panel product warranty, panel performance warranty, inverter warranty, battery warranty, workmanship warranty and any insurance-backed warranty. The most important question is not only how long the warranty is. It is who is responsible if something goes wrong.
5. Watch for quote red flags
A quote is not automatically bad because it is short or cheap. But vague wording should slow you down.
Common warning signs include pressure to pay a deposit before the quote is clear, savings claims without assumptions, battery recommendations without usage data, warranties described with one impressive number, unclear paperwork responsibility and refusal to put answers in writing.
For a fuller warning-sign list, read the related guide to common solar quote red flags.
6. Ask every installer the same questions
The fairest way to compare quotes is to put the same questions to each installer and record the answers side by side. That turns a sales conversation into a structured comparison and makes real differences between installers visible.
The questions worth asking - about system size, warranties, paperwork, battery value and aftercare - are set out in full in our guide to the questions to ask every installer, with a short explanation of why each one matters.
Before you pay a deposit
Do not pay a deposit until you understand the final price, the system specification, what happens if survey findings change the quote, cancellation terms, installation timeline, warranty responsibility, paperwork responsibility and aftercare route.
If the installer is good, clear questions should not be a problem.
FAQ
How many solar quotes should I get in the UK?
A sensible starting point is three quotes. Energy Saving Trust recommends getting quotes from at least three MCS-certified installers.
Should I choose the cheapest solar quote?
Not automatically. A cheaper quote may be a good deal, but it may also include a smaller system, fewer extras, weaker aftercare or missing assumptions. Compare the specification before comparing price.
What is MCS certification?
MCS certification is a recognised UK standard for low-carbon installations and installers. For solar buyers, it is often relevant to consumer protection, installer standards and export tariff eligibility.
Who handles DNO notification for solar panels?
A solar PV system must be registered or notified to the Distribution Network Operator. For smaller systems this may be a G98 notification after commissioning; larger systems may need a G99 application before connection.
Do all suppliers pay the same SEG export rate?
No. Smart Export Guarantee terms are set by SEG licensees, so rates, contract lengths and terms can vary. Check the current supplier terms before relying on export income.
Sources
- Energy Saving Trust: Solar panels
- Ofgem: Smart Export Guarantee
- National Grid: G98 microgeneration
- National Grid: G99 generation
Disclaimer
This article is general information only. It is not financial, legal, tax, technical, engineering or regulated professional advice. Always verify quote details, warranty terms, certification status, tariff terms and installer responsibilities directly before signing or paying a deposit.