Aurora Sales Mode vs Design Mode

Key Takeaways

• Aurora Sales Mode: fast, simplified loss factors, customer-facing.
• Aurora Design Mode: NREL SAM-driven, granular, permit-stage.
• Use Sales Mode for proposals; Design Mode for final design.
• Sales Mode accuracy ±5-8%; Design Mode ±3-5%.

Why Aurora Splits the Workflow Into Two Modes

Aurora built Sales Mode and Design Mode around two different jobs that happen at two different points in a project’s life. Early on, a sales rep needs a production estimate and a proposal fast enough to close a deal on a first call, accuracy within ±5-8% is acceptable because the customer is comparing options, not signing off on a stamped engineering package.

Once a project is under contract, the same site model needs to hold up to permit reviewers and financiers, so Aurora runs it through SAM, NREL’s System Advisor Model, with finer loss granularity to tighten the estimate to ±3-5%.

What Changes Under the Hood

The two modes don’t just apply a different rounding rule; Design Mode recalculates the same roof and shading model with more loss factors broken out individually, soiling, module mismatch, wiring, inverter clipping, and temperature derate, rather than folding them into one blanket assumption the way Sales Mode does.

Both modes typically draw from the same underlying irradiance dataset (for US projects, this is usually NSRDB/TMY3 data), so the accuracy gap comes from how finely each mode processes that data, not from a different weather source.

A Simple Illustration

Take a straightforward residential roof with one section of afternoon tree shading. In Sales Mode, Aurora applies a simplified shading and loss factor to produce an annual production number quickly enough to show the homeowner on the spot.

Re-running the identical layout in Design Mode, same roof, same array, same shading obstruction, pushes that estimate through NREL SAM’s more granular hourly loss modeling, which can nudge the annual yield figure by a few percentage points once the finer-grained shading and derate calculations are applied. That shift is exactly why permit-stage and financing documents should be built from Design Mode output rather than the original sales estimate.

Related Reading

Aurora’s dual-mode workflow is one reason it remains a common pick for US residential and light-commercial teams, though plenty of installers weigh it against alternatives before committing, see our comparisons in Aurora vs HelioScope: 2026 Head-to-Head for Installers and Aurora Solar Alternatives for US Installers in 2026.

For projects where even Design Mode’s SAM-driven output isn’t granular enough, think bifacial gain calculations or complex row-to-row shading on a commercial array, engineering teams often pair Aurora’s site model with a dedicated yield-simulation pass, a workflow covered in Advanced PVsyst Analysis: How Accurate Yield Predictions Save Millions.

Teams still deciding whether Aurora’s two-mode approach fits their stack can also see how it stacks up against alternatives in SurgePV’s Aurora Solar comparison.

For a tool-level comparison, see PVsyst vs Aurora Solar.

Disclosure: SurgePV is a Heaven Designs group company.