You've had a solar installer round, they've looked at your roof, and now there's a quote sitting in your inbox. It's got numbers, brand names, and technical specs you've never seen before. How do you know if it's any good?
Most homeowners focus on the total price. That's understandable, but it's also how people end up overpaying or, worse, getting low-quality equipment they'll regret in five years. A solar quote is more than a price tag — it's a proposal for a system that should last 25+ years on your roof.
Here's what to actually look at.
1. Price Per Watt, Not Total Price
The total price of a solar installation varies hugely depending on system size, battery inclusion, and where you live. A £12,000 quote means nothing in isolation. What matters is the price per watt (or per kilowatt-peak).
To calculate it, divide the total price by the system size in watts. For example, if your quote is £6,000 for a 4kWp system, that's £1.50 per watt. If it includes a battery, separate the battery cost first and calculate the solar-only price per watt.
What's fair in 2026?
For solar panels alone (no battery), expect roughly £0.80–£1.20 per watt depending on equipment quality and your region. Systems with batteries typically come in at £1.00–£1.50 per watt for the combined package. Anything significantly above these ranges deserves a closer look.
2. Panel Brand and Specifications
Not all solar panels are equal. Your quote should name the specific panel model, not just "400W panels." Look for the manufacturer, the model number, the wattage per panel, and the efficiency rating.
Premium panels from manufacturers like Aiko, LONGi, and Canadian Solar tend to offer higher efficiency (above 21%), better warranties (25 years on product and performance), and more reliable long-term output. Budget panels might save a few hundred pounds upfront but can degrade faster and produce less energy over their lifetime.
If the quote just says "tier 1 panels" without naming them, ask which specific model. Vagueness here is a red flag.
3. Inverter Quality
The inverter converts the direct current (DC) your panels produce into alternating current (AC) your home can use. It's the hardest-working component in the system and usually the first thing to fail if it's cheap.
Look for recognised inverter brands like Sigenergy, SolarEdge, Enphase, GivEnergy, or Huawei. Your quote should state the brand, model, power rating, and warranty period. A good inverter comes with at least a 10-year warranty, and many premium options now offer 12–15 years.
If the quote doesn't mention the inverter at all, that's a significant red flag.
4. Battery Details (If Included)
If your quote includes battery storage, check the brand, usable capacity (in kWh), the number of charge cycles, and the warranty. The usable capacity is what matters — not the total capacity, which includes a reserve the system won't let you access.
Battery pricing benchmark
A fair price for battery storage in 2026 is roughly £400–£700 per usable kWh, depending on the brand. So a 10kWh usable battery should cost between £4,000 and £7,000 as part of an installation package.
5. MCS Certification
MCS (Microgeneration Certification Scheme) certification is essential. Without it, you won't be eligible for the Smart Export Guarantee (SEG), which pays you for electricity you export back to the grid. It also means the installation hasn't been done to the recognised industry standard.
Your quote should clearly state that the installer is MCS-certified. You can verify this yourself at mcscertified.com by searching for the company name.
6. Who Actually Does the Installation?
This is one of the most overlooked parts of a solar quote. Some companies that sell solar panels don't install them — they subcontract the work to a third party. This isn't necessarily bad, but it creates risk: the company you're paying may not be the one on your roof, and accountability gets murky if something goes wrong.
Ask directly: "Will your own team install this, or do you use subcontractors?" If they subcontract, ask who the subcontractor is and whether they're MCS-certified in their own right.
7. Warranty and Aftercare
A good solar quote will clearly outline three separate warranties: the panel product warranty (typically 25 years), the panel performance warranty (guaranteeing a minimum output after 25–30 years), and the inverter warranty (10–15 years). There should also be a workmanship warranty covering the installation itself — usually 5–10 years.
If the quote bundles everything into a single "25-year warranty" without specifying what's covered, ask for a breakdown.
8. What's Missing From the Quote?
Good quotes include scaffolding costs, any electrical upgrades needed (like a new consumer unit), VAT status (solar installations are currently VAT-free in the UK), planning permission notes, and a timeline for installation. If any of these are absent, the "final" price might not be final at all.
The Quick Checklist
- Price per watt calculated and within market range
- Specific panel brand and model named
- Inverter brand, model, and warranty stated
- Battery specs clear (if included)
- MCS certification confirmed
- Installation team clarified (in-house or subcontractor)
- Warranties broken down individually
- All costs included (scaffolding, electrical work, VAT)