The answer
Is satellite imagery enough for a quote?
Satellite imagery is a useful starting point, not a complete roof survey. Before final design, someone must establish roof condition and structure, shade, safe access, the panel layout and electrical cable route.
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Is the roof ready to carry panels for years?
A satellite image can estimate orientation and outline area, but it cannot show the condition of slates, tiles, fixings or roof timbers. If the covering is near replacement, installing now may mean paying later to remove and reinstall the array. Ask who will check structural capacity and the proposed fixing method, especially on an older or unusual roof.
The usable rectangle is smaller than the roof looks from the street. Chimneys, dormers, rooflights, vents and safe edge clearances all reduce panel area. Sketch a dimensioned panel layout on the actual roof, not just a number of panels in a sales quote. Where the building is listed or in a sensitive setting, flag planning questions before treating the layout as settled.
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How much shade and generation should you expect?
Shade from trees or adjoining buildings moves through the day and across seasons. A photograph taken at noon in summer can miss a winter obstruction or a shaded morning. Ask what shade data went into the generation forecast and whether individual panels or strings are affected.
The estimate should state orientation, roof pitch, installed capacity and expected annual generation, then show how much of that electricity the property is likely to use. A good south-facing yield does not guarantee a good financial result if the building is empty when generation is highest. Discuss battery storage only after that demand pattern is understood.
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Where will the rest of the system go?
The survey should locate the inverter, isolators and cable route to the electrical board. Check access for installation, scaffold or other safe working arrangements, and future roof maintenance. Ask whether the existing electrical connection and proposed inverter need network notification or approval.
Before accepting a fixed price, make a short list of what the survey has not confirmed: roof repairs, structural questions, access, planning, electrical upgrades or export limits. A transparent provisional quote is more useful than a confident price that excludes the difficult parts.
Where this guidance comes from
Check the original guidance.
These primary sources support the technical or scheme points above. Rules can change; follow the current source before making a commitment.
Apply this to your property
Find out what your roof can really support.
FLO's free solar survey checks the roof and electrical route before designing around an online estimate.