Mieterstrom-Rechner

A tool for solar installers to configure a "Mieterstrom" (tenant electricity) offer for a building, calculate its economics, and generate customer-facing PDF documents (offer, cost/benefit analysis, flyer).

Built with Next.js 16 (App Router), React 19, and Tailwind CSS.

Features

• Building & customer input — capture the customer, building address, and energy system details (PV size, storage, Messkonzept/metering concept).
• Consumption & pricing — model tenant consumption and set up the Mieterstrom pricing.
• Live economics ("Wirtschaftlichkeit") — investment, revenue, operating cost, and amortization calculated as inputs change.
• Address map preview — shows the building location on a map alongside the form.
• PDF export — generates an offer ("Angebot"), a cost/benefit analysis, and/or a flyer as a print-ready PDF, with an optional email step.
• Embeddable — supports an ?embed=1 mode for embedding the tool in another page (e.g. an iframe).

Getting Started

Install dependencies and run the development server:

npm install
npm run dev

Open http://localhost:3000 in your browser. The app auto-reloads as you edit files under app/.

Other scripts:

npm run build   # production build
npm run start   # run a production build
npm run lint    # eslint

Project structure

• app/ — Next.js App Router entry point (page.tsx, layout.tsx).
• components/form/ — input boxes for the building, energy system, consumption, and pricing.
• components/preview/ — the offer, cost/benefit, and flyer panels, plus the print/PDF layout.
• components/ui/ — shared UI pieces (logo upload, collapsible sections, icons, loading screen).
• hooks/useMieterstromCalculator.ts — central state and calculation hook driving the whole form/preview flow.
• lib/calculator.ts — the Mieterstrom economics calculations.
• lib/generatePdf.ts — renders the preview to a PDF and names the output file.
• lib/charts.ts / lib/umami.ts — chart helpers and analytics event tracking.

Documentation

• docs/calculator.md — how lib/calculator.ts turns form inputs into Angebot pricing, Wirtschaftlichkeit projections, and flyer figures, including the self-consumption approximation and the Mieterstrom pricing models.

Notes

• This project is on Next.js 16, which has breaking changes vs. earlier versions — check node_modules/next/dist/docs/ before assuming an API from older Next.js docs still applies.
• PDF generation runs client-side via html2canvas-pro and jspdf (see lib/generatePdf.ts).