A design should fit the roof—not fight it
Usable roof area, shading, rooflights and safe access all shape the final layout.
The main quotation variables
Panel count and inverter capacity affect equipment cost, but roof type, height, scaffold requirements, access and cable routes can be equally important. Slate, tile and flat roofs use different mounting details. Roof repairs or structural work should be identified before panels cover the affected area.
The electrical scope depends on the consumer unit, earthing, meter position, proposed inverter location and grid-connection requirements. Battery storage, backup circuits, EV charging, bird protection and monitoring choices add separate design and installation considerations.
Compare the scope, not only the total
A useful quotation identifies the proposed equipment, system size, expected generation, access provision, electrical work, grid paperwork, monitoring and handover. It should say which items are included and which conditions could require a change after survey.
Savings estimates should disclose import price, export rate, self-consumption and degradation assumptions. A lower total price is difficult to assess if the underlying roof work, certification or performance assumptions are unclear.
VAT and finance need current checks
Qualifying installations of certain energy-saving materials in residential accommodation in Great Britain are currently zero-rated for VAT until 31 March 2027. Eligibility depends on the installation and current tax rules, so the quotation should show the VAT treatment rather than treating it as universal.
If finance is used, compare the total amount repayable, term and interest with the cash price and expected energy benefit. Estimated bill savings should not be presented as a guaranteed way to cover repayments.
Common questions
- Can I get an accurate solar quote without a survey?
- Remote information can support an initial assessment, but roof condition, access, shading, electrical details and cable routes need appropriate checks before the final design and price are agreed.
- Is the cheapest solar quote usually the best value?
- Not necessarily. Compare system design, equipment, access, electrical scope, certification, performance assumptions, exclusions and support alongside the total price.