Path-Q Solar

How should I compare quotes that use different numbers of panels but promise similar output?

Answer

Compare expected annual and hourly production, panel and inverter specifications, layout, shading assumptions, degradation assumptions, clipping or curtailment, and total installed cost rather than panel count. Fewer higher-output panels can produce similar energy, while roof layout and system losses may explain the difference.

Key points

  • Panel wattage alone does not establish annual generation.
  • Roof orientation, tilt, shading, temperature, wiring, inverter design, and export limits affect output.
  • Compare usable production and self-consumption, not only the array's nameplate capacity.
  • Check whether similar output is modeled under identical weather and load assumptions.

What it depends on

  • Panel and inverter specifications
  • Roof layout and shading
  • Production-model assumptions
  • Export limits and battery configuration

Risks and trade-offs

  • A larger nameplate system may not produce more usable energy if constrained by shading or export limits.
  • A compact design may cost more per panel or require different equipment.
  • Production estimates can look similar while warranties, serviceability, and future expansion differ.

Information you may need

  • Equipment model numbers and ratings
  • Layout and shading analysis
  • Annual and monthly production estimates
  • Loss, degradation, curtailment, and export assumptions

Your next step

What to do next

Ask installers to rerun both proposals using the same production assumptions and compare annual usable energy, total cost, and equipment scope.

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SQ01240