The headline panel price is only part of a solar quotation. A useful comparison includes the complete installed system, realistic savings assumptions and the costs you may face later.
A sensible starting point
Energy Saving Trust’s April 2026 guidance gives about £6,100 for a typical 3.5 kWp domestic solar system. Your price may be higher or lower depending on roof access, scaffolding, panel and inverter choice, electrical work, monitoring, grid requirements and whether roof repairs are needed.
What should the quotation include?
- Panel make, model, quantity and total kWp
- Inverter type and optimisers, if genuinely required
- Mounting system, scaffolding and roof-access costs
- Electrical protection, generation meter and monitoring
- DNO application or notification
- Workmanship and product warranties
- MCS certification and handover documents
- Waste removal and any making good
Optional extras
| Extra | Typical consideration |
|---|---|
| Battery | A 5 kWh system is around £4,600 in Energy Saving Trust guidance. Test its payback separately. |
| Optimisers | Useful for some shading or complex roofs; not automatically beneficial on every roof. |
| Immersion diverter | Can use surplus solar for hot water where a suitable cylinder exists. |
| EV charger | May improve daytime self-use if the car is often at home. |
| Bird protection | Worth pricing where nesting is a known local issue. |
How to compare payback claims
Ask every installer to state annual generation, assumed self-consumption, electricity import price, export price, degradation and maintenance assumptions. A quotation that hides these inputs is not genuinely comparable.
- Compare the same system size and specification.
- Separate bill savings from export income.
- Do not treat a battery as free just because it is bundled.
- Stress-test the estimate using lower electricity prices and lower self-use.
- Check whether inverter or battery replacement is allowed for.
Frequently asked questions
Is the cheapest quote best?
Not necessarily. Certification, equipment, survey quality, warranty protection and the financial health of the contracting company all matter.
Should I finance the system?
Compare total repayable cost, not only the monthly payment. Interest can materially extend the true payback period.
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