What it is
Heizkostenvergleich24 is the tool I wanted heating contractors (SHK and electrical trades) to have in front of them when they sit at a customer’s kitchen table: a digital heating comparison, a certified heat-load calculation, and the complete BEG funding handling, in one place. The original calculation engine was an old PHP script. I rebuilt it as a Nuxt web app on top of a Python Firebase Cloud Function so the same numbers can travel from the contractor’s screen straight into the customer’s PDF.
Why we shifted to the trade
Property owners want a one-click number. Trade specialists need to defend that number for the next twenty years. The new positioning puts the Fachhandwerker at the center: white-label PDF exports with their logo, project archive for variants and customers, configurable cost parameters, and the BEG paperwork done by us instead of by them. The free public calculator now mainly serves as a lead source for the partner network.
Features
- Firebase-based accounts with roles for Admin and Fachhandwerker (heating contractor)
- White-label PDF exports with the contractor’s logo, contact details, and color
- Project archive, variants, comments, and team sharing for SHK and electrical businesses
- Side-by-side comparison of heating types with regional prices, subsidies, 20-year forecasts
- Editable table UI with unsaved-changes detection
- Heating-cost calculator running as a Firebase Cloud Function (Python)
- Heat-load calculation per DIN EN 12831, manually validated by partner engineers
- BEG EM funding handling (application, communication with the funding body, evidence management)
- Cloud-synced via Firestore, responsive on web and mobile
Architecture
- Nuxt web app: contractor-facing application (
vue_app/) - Firebase Cloud Functions (Python): heating-cost calculation logic, ported from a legacy PHP implementation, modular across all heating types
- Astro landing page: positioning for heating contractors, free calculator iframe, partner program (
landingpage/) - Firebase Hosting: landing and app deployment
- Cloud Firestore: storage for users, projects, heating data, partner datasets
Tech highlights
app | Nuxt (Vue, TypeScript) |
engine | Python, Firebase Cloud Functions |
data | Firestore, Firebase Auth |
hosting | Firebase Hosting |
... | and more |
My role
Full-stack: architecture, Nuxt app, Python calculation backend, Firebase setup, landing page, repositioning toward the trade, deployment.