WhatsApp Solar ROI Proposal Automation (n8n + OpenAI + Drive)

Generate WhatsApp solar ROI proposals automatically—from bill photo to PDF (n8n + OpenAI + Drive)

Turn every WhatsApp solar lead into a data-backed ROI proposal in minutes. This WhatsApp Solar ROI Proposal Automation workflow pulls rooftop solar details from an uploaded electricity bill using OpenAI (GPT-4o), calculates system sizing, PM Surya Ghar subsidy, payback/EMI, and then delivers a branded PDF proposal via WhatsApp—while tracking everything in Google Sheets and archiving documents in Google Drive.

What this workflow does

• Triggers when a lead messages on WhatsApp or submits an n8n web form with an electricity bill image.
• For WhatsApp leads, it checks whether an image is included; if not or unreadable, it requests a clearer bill photo.
• Sends the bill image to OpenAI (GPT-4o) to extract consumption, tariff, sanctioned load, and usage history, then validates the extraction.
• Calculates recommended system size, expected generation, PM Surya Ghar subsidy, net cost, payback period, EMI estimate, and 25-year savings.
• Assigns a HOT/WARM/NURTURE lead score based on the extracted inputs/results.
• Generates proposal copy using OpenAI (gpt-4o-mini), builds a proposal HTML, renders a QuickChart savings graph, and converts it to a PDF via a self-hosted Gotenberg endpoint.
• Archives the PDF to Google Drive, sends the PDF and a Cal.com site-survey booking link on WhatsApp, and upserts lead/proposal details into Google Sheets.

Use cases

• Solar installers responding to WhatsApp leads with instant ROI proposals after the customer shares a bill photo.
• Automation engineers building an end-to-end WhatsApp → OCR → ROI calc → PDF → Drive/Sheets pipeline in n8n.
• Teams reducing manual proposal work while maintaining consistent ROI calculations and follow-up tracking.

Technical details

• Integrations/logic: WhatsApp, webhook, n8n form trigger, OpenAI (GPT-4o + gpt-4o-mini), QuickChart, Gotenberg (PDF render), Google Sheets, Google Drive, Cal.com booking updates.
• n8n node types mentioned: if, code, switch, webhook, sticky note.