The Challenge: Navigating Electrification Without the Sales Pitch
Replacing fossil gas furnaces, water heaters, cooktops, and gas-powered cars with clean electric heat pumps, induction stoves, and EVs is the single most effective climate action an individual household can take.
However, homeowners attempting this transition today face a fragmented landscape: contractor quotes with massive markups, confusing solar and battery lease proposals, and contradictory advice on whether a 100A or 200A electrical service panel upgrade is needed. Most online calculators are sales funnels engineered to capture contact information rather than provide neutral, physics-based guidance.
Our Core Principle: WhyWatt? HEX has no commercial affiliates, sells no equipment, and takes no commissions. Built through open development with community input: methods, data, and testing procedures are openly shared. Volunteer to get access to code and support it.
The WhyWatt? HEX Approach: "Your Journey" vs. "Do Nothing"
Home electrification is rarely an overnight event; it is a multi-year journey. A heat pump water heater might make sense this year because the old tank is failing, while a central heat pump HVAC upgrade might wait until your existing AC reaches end of life.
WhyWatt? Home Electrification eXplorer models your household over a 20-year horizon by executing two parallel simulations simultaneously:
- Your Electrification Journey: You choose which appliances to swap, when to install them, and whether to add rooftop solar or home battery storage (e.g. Tesla Powerwall 3).
- The "Do Nothing" Baseline: The model runs an identical home that stays on gas. When existing appliances reach the end of their useful lifespans, they are replaced like-for-like with gas equipment, continuing to burn fuel as utility gas rates escalate.
By stepping both homes through each calendar year, WhyWatt? HEX calculates the real cumulative cashflow, annual utility bills, maintenance expenses, social cost of carbon avoided, and the exact year your clean energy investments achieve net payback.
Built on Rigorous California Data
Generalizations fail because energy economics are hyper-local. WhyWatt? HEX grounds every simulation in authoritative, checksum-pinned datasets looked up by ZIP code:
- CEC Climate Zones & TMYx Weather: High-resolution typical meteorological year weather data matching your specific California microclimate zone.
- NREL ResStock 2025.1 Load Profiles: 24-hour hourly load shapes for each appliance and climate zone, accurately modeling heating, cooling, and water draw patterns.
- Actual Utility Tariffs from URDB: Real time-of-use (TOU) rate schedules from PG&E, SCE, SDG&E, SMUD, and municipal utilities, including peak/off-peak windows, baseline allowances, and monthly fixed charges.
- PVWatts & NEM 3.0 / Net Billing: Hourly solar generation profiles paired with the CPUC Avoided Cost Calculator (ACC) to accurately reflect modern export compensation.
- Historically-Calibrated Rate Projections: Tested against California energy escalation trends (Conservative, Moderate, and Stress projections) so you aren't surprised by future price spikes.
Learn How It's Built: Curious about the exact equations and algorithms? Visit our interactive Architecture Explainer to explore the offline pipelines, appliance models, and Mesa simulation loop.
Technology & Architecture
WhyWatt? HEX is engineered with a modern, high-performance Python data science stack:
- Mesa Framework: An agent-based simulation architecture that steps each household model year by year, managing equipment state transitions and financial bookkeeping.
- Solara Web Framework: Provides a reactive, pure-Python UI running directly in the browser with near-instant recalculations as you adjust sliders.
- Offline Data Pipelines: Robust Python harvesters that pre-compute and validate massive datasets (NREL, URDB, PVWatts) to ensure the web app remains blisteringly fast.
Who We Are
WhyWatt? HEX was conceived and developed by California community clean energy advocates, engineers, and volunteers who believe that open data is essential for equitable climate progress.
The project is supported by the Electrification Collaboration, a coalition of community organizations and volunteers helping neighbors eliminate fossil gas from their homes and vehicles.
Get Involved
Whether you are a homeowner running scenarios for your house, a city advocate hosting community workshops, or a modeler interested in contributing to development, we welcome you to join our growing community! Methods, data, and testing procedures are openly shared, and you can volunteer to get access to code and support it.