1. Quantify shading
Model shading month by month using the actual module layout. A microinverter tracks its module independently but cannot recover missing sunlight. Compare results with the other system’s bypass diodes, strings and MPPTs; shade does not automatically mean losing the output of an entire string-inverter system.
2. Account for roof orientations
Check how each roof plane is connected and tracked. Microinverters, optimisers or separate MPPT inputs can suit different layouts. Compare voltage, current, capacity and simulated generation rather than excluding all string inverters for an east-west roof.
3. Define the monitoring you need
Module-level monitoring can help locate an output discrepancy. Ask which data you can see, how often it updates, how long it is retained and which access the owner receives. Define who handles alerts and communication faults; a dashboard does not guarantee instant detection of every failure.
4. Verify the Swiss backup configuration
Do not infer backup capability from the IQ8 name alone. Confirm the inverter, battery, controller, switching and circuit combination against current Swiss documentation. Ask which phases remain powered, the power limits, reserve and restart conditions; a US System Controller 2 data sheet does not validate a Swiss installation.
5. Plan an expansion
An expansion still needs assessment. Confirm module compatibility, AC circuits, protective devices, gateway, cabling and grid requirements. Ask about the procedures and cost of the proposed expansion before treating additional modules as a simple automatic addition.
6. Compare warranties and total cost
Compare two quotations with the same modules, capacity and scope. Include the gateway, cables, protective devices, installation, roof access and service. Read the model’s warranty for duration, registration, exclusions, transport, replacement and labour; a warranty does not remove the need to monitor the system.