Selecting the system and capacity
The site assessment should check usable roof area, structural condition, shade, maintenance access and cable routes. A capacity recommendation should follow these checks and a review of electricity consumption. For shared buildings, confirm who can authorise the work and how it will be coordinated.
System size should reflect the property rather than a standard package. A larger system is not automatically a better fit if the roof, electrical connection or consumption pattern cannot support the proposal. Ask why the recommended capacity suits your requirement and how future changes have been considered.
A standard on-grid installation normally shuts down during a grid outage. Backup requires an appropriate design and compatible equipment, which should be discussed separately.