WhyWatt?
Home Electrification Explorer
Map your home electrification journey. Weigh the cost-benefit, then decide.
WhyWatt? is a community-developed, open and transparent tool to explore your electrification options, timeline, and benefits for your home.
Open source & method
CA climate zones + IOU rates
20-yr cost trajectories
Your journey — each device swap, placed on a 20-year timeline.
vs. doing nothing — the same devices, replaced like-for-like.
WhyWatt? · community electrification collaboration
02 · The interface · 1 of 4
The cockpit — your bottom line, up front
① The verdict — payback & social cost avoided.
② Two futures, side by side.
③ Panel guidance — amps vs. capacity.
- The verdict. Net result over 20 years, here −$10,216, with +$21,258 in net social cost avoided.
- Two futures, one glance. Your journey $132,691 vs. do nothing $122,475.
- Left chart. Select a graph from the dropdown — here, cumulative cost: both paths year by year, with gas- and solar-saves shaded.
- Right chart. Select a graph from the dropdown to compare — here, the journey timeline of every device swap.
- Panel guidance. Present 41 A vs. 150 A peak — flags when an upgrade is needed.
WhyWatt? · interface · the cockpit
03 · The interface · 2 of 4
Set up your home
- Home & Solar. ZIP, bedrooms, square footage, and California climate zone — plus an optional solar + battery add.
- Energy & Prices. Model horizon (20 yrs) and rate models: electricity +7%/yr, gas +8%/yr, gasoline and EV-charging rates too.
- Social & Health. Optional climate cost (CO₂ + methane, 1.07 $/therm) and air-quality cost (1.23 $/therm), plus gasoline externalities.
- Sensible defaults. Everything is pre-filled for a Bay Area home — adjust only what you know.
Three panels — collapse together when you're done.
WhyWatt? · interface · setup
04 · The interface · 3 of 4
Plan your electrification journey
Major loads — HVAC, water heater, transportation.
Other appliances — cooktop, dryer, panel, baseload.
- Six device cards. Each holds a starting fuel, a swap year slider, and install / rebate / net cost.
- HVAC → heat pump, Yr 3 · 2027, net $10,500.
- Water heater → HPWH, Yr 5 · 2029, net $2,000.
- Transportation. Add an EV charger from miles driven, MPG, and efficiency.
- Cooktop, dryer, panel & baseload. The rest of the home, each on its own timeline.
WhyWatt? · interface · journey
05 · The interface · 4 of 4
Go deep — detail page per device
Every card opens a full detail page. Here's the water heater — gas today, heat pump planned for year 5.
- Side-by-side physics. Current gas WH ~182 therms/yr vs. replacement HPWH ~993 kWh/yr.
- Real parameters. Daily hot water, inlet & setpoint temps, UEF 0.65 → 3.5, tank size, age & lifespan.
- Electrical reality. Shows the breaker the HPWH needs — 240 V · 15 A.
- Costs & rebates. Install $2,500 − rebate $500 = net $2,000.
WhyWatt? · interface · detail pages
Scenario 01
Replace-on-failure
The Technophile
Researches carefully, replaces on failure, and isn't especially price-sensitive. Goes heat pump for both heating and hot water.
- No real payback. Even at year 22 the journey is only +$632 ahead on energy alone — essentially break-even.
- Social cost makes the case. Count avoided CO₂, methane & air-quality harm and it's +$20,561 better — that's where the real value sits.
- You're buying cooling, too. The Bay Area default has no AC. The heat pump adds cooling the home never had — so part of the spend buys comfort, not just fuel savings.
WhyWatt? · scenario 01
Scenario 02
Appliance refresh + EV
The EV Family
An EV-owning, socially-minded household — adds a charger, moves appliances off gas, and layers in solar + battery.
- The panel becomes the constraint. Adding EV charging pushes peak demand to 119 A — past the 100 A limit, forcing a 200 A panel upgrade.
- Solar is what tips it positive. With solar + battery layered in, the journey reaches payback in year 13 (2037), +$11,380 ahead — without it, it stays underwater.
- Strong social return, too. +$20,599 in avoided climate & health cost on top.
WhyWatt? · scenario 02