Comparing solar quotes: use the same brief and scope
Sources checked
Compare offers for the same brief and completed scope, rather than final price alone. Separate panel power in kWp, inverter power in kW and battery capacity in kWh. Confirm exact models, installation work, backup and exclusions in each offer.
Build a like-for-like checklist
Ask for roof assessment, layout, mounting, cable routes, protection, metering, switchboard changes, transport, inspection, commissioning and distribution administration. Specify VAT and support separately so that a subsidised headline does not obscure the gross invoice.
For storage, compare usable capacity, continuous power and the supported battery/inverter combination. For backup, identify circuits, phases, switching and runtime assumptions.
Ask how savings were calculated
The estimate should explain generation, direct use, battery losses, exports, import/export prices, fees and operating costs. An annual production figure multiplied by the full retail bill rate is not a complete savings model.
Compare warranties, claim responsibility, payment stages, delivery and service as well as equipment. Ask about omitted work before signing, and keep a written record of changes to the agreed supply.