Shaded roof? String inverters, optimisers and microinverters

Map the shade before choosing equipment

Shade from a chimney for a short period differs from a tree covering most of a roof through winter. The location, duration and season of shading determine whether a roof face is worth using. No inverter can recreate sunlight that never reaches a panel. Start a solar-system design discussion with the roof and load profile, not a preferred brand.

Ask the designer to compare layouts that avoid heavily shaded areas with layouts that use extra electronics. A smaller well-exposed array may be worth comparing with a larger partially shaded one. The assessment should explain assumptions about tree growth and nearby development; a single summer aerial image cannot establish year-round performance.

Understand the architectural differences

Partial shade is not the only design variable

String designs must account for panel grouping and the inverter’s electrical operating ranges. Optimisers and microinverters can give panels more independent operation, which can be useful across different exposures. They do not remove all design constraints or turn a persistently shaded roof into a strong generator. Model-specific equipment rules still apply.

Compare lifetime access as well as output

Panel-level electronics add equipment beneath the array. Ask how a failed device would be identified and accessed, who covers labour and what roof access might cost. A central inverter is often easier to reach, but a fault there can affect more of the system at once. Neither fact alone decides the best option.

Monitoring detail is another difference. Panel-level views may make a local issue easier to spot, while some string systems expose less granular data. The monitoring explainer describes what the measured figures can and cannot tell you. Confirm whether consumption monitoring is included; a panel map is not automatically whole-home monitoring.

Ask for a comparable proposal

• Use the same roof, weather and shading assumptions for each alternative.
• Show proposed panel positions and excluded roof areas.
• State equipment compatibility, monitoring functions and warranty exclusions.
• Separate predicted energy from guaranteed outcomes; request uncertainty or sensitivity cases.
• Include access, replacement labour and future expansion constraints.

For an existing array, read the expansion checklist before assuming the new architecture can be attached to the old equipment. For a house still being designed, new-home solar provisions may help avoid unnecessary roof obstructions in the first place.

A useful conclusion is conditional

The outcome should explain why the chosen layout and inverter suit this roof, how shade was assessed and what remains uncertain. It should not simply say that one technology is always better. Retain the design assumptions with the site-assessment worksheet so future changes to trees, roof structures or loads can be compared against the original decision.