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How long does it take to install commercial rooftop solar?

Project timelines include engineering, permitting, utility approvals, equipment procurement, and onsite installation.

UpdatedJune 2026
Read time4 min read
CategoryCommercial Rooftop Solar
Reviewed byGI Engineering
Clear answer

Clear answer, explained.

Smaller systems may be installed within days once approvals are in place, while larger or more complex projects require longer coordination and construction periods. Final commissioning occurs after inspections and utility permission to operate.


Key points

What this means in practice.

  • Typical total project timeline: 4–12 weeks
  • Onsite installation: a few days to several weeks
  • Larger systems require longer engineering and permitting
  • Utility interconnection approval can affect timelines
  • Weather and roof access can impact construction schedules
  • Commissioning occurs after inspections and meter configuration

When this applies

Best-fit environments.

  • Commercial rooftop solar projects from ~50 kW to multi-MW Office, warehouse, retail, and industrial buildings
  • Grid-connected systems requiring utility interconnection
  • New installations or portfolio rollouts

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