A personal home battery ROI calculator.
Calculate payback periods for popular home battery systems based on your utility, rate plan, and energy profile. Compare Tesla Powerwall 3, Enphase IQ 5P, Pila Mesh, and Base Power side-by-side. Optimized for California NEM 3.0, New England ConnectedSolutions, and ERCOT VPP programs.
- 16 Utilities — PG&E, SCE, SDG&E, Con Edison, Eversource, and more
- 35 Rate Plans — TOU schedules with peak/off-peak/super-off-peak tiers
- 4 Battery Systems — Purchase vs. lease models with real specs & pricing
- NEM 3.0 Support — California net billing export rate calculations
- VPP Earnings — ELRP, ConnectedSolutions, ERCOT, and more
- Show the Math — Expandable formula breakdowns on every card
- Charts — Canvas-based payback timeline, savings donut, 10-year cumulative
# No build step needed — just serve the files
python3 -m http.server 8765
# or
npx serve .- Select your utility and rate plan
- Enter your monthly bill and home specs
- Set your priorities — backup value, VPP participation, tax credits
- Compare results — 4 battery systems with payback periods, annual savings, and 10-year net benefit
- Zero dependencies — Pure HTML, CSS, JavaScript (ES modules)
- Dark glassmorphism UI — Inter font, gradient accents, backdrop-blur cards
- Canvas charts — No charting library needed
- Responsive — Mobile-first, works on all screen sizes
Rate data is accurate as of Q1 2026 and sourced from published utility tariffs. To update rates, edit the files in js/data/.
See CHANGELOG.md for details on recent releases and updates.
This project is licensed under the PolyForm Noncommercial License 1.0.0. It is free for noncommercial use; commercial use requires the author's permission.