WhatSun — Your Curious Energy Advisor for solar + battery homes
Your Curious Energy Advisor
What can the sun do for you?
Learn more inside.
Tesla Home runs your hardware. WhatSun runs your morning — a 2-minute plain-English plan for your solar, your Powerwalls, both cars, and everyone in the house.
No dashboards to babysit, no automations to fight, no setup. Works in any browser.
Start free forever — no credit card needed · 5-minute setup · Works on any device
Try it without signing in
Move the sun, change the weather, plug in the car — watch the plan rewrite itself.
Power sold to the utility earns about 5¢/kWh — the same power is worth 42¢ in your car or battery.
Play with the day
No account, no Tesla login. Set your own system size and watch the plan change.
18,250 mi/yr · gas + maintenance $5183.00/yr vs $953.74/yr electric, with 80% of charging from your own sun.
20,033 kWh of sun a year from 11.2 kW — 75% powers the house and cars, the rest sells back at 5¢/kWh.
Big day — about 65 kWh. The car can take 18 kWh after 10:30 AM and the Powerwall still fills up. So far you've kept $14.66 off the bill.
Demo home with one Powerwall and one Model Y, priced at 42¢/kWh. Connect your own system for real plans.
Emergency buttons for bad days
When the grid wobbles or a storm rolls in, lift a safety cover and press. Go off grid runs the house on sun and Powerwall alone. Bunker 100% turns on Tesla Storm Watch and fills the battery. One lever puts everything back.
Live weather alerts show on the console, and grid outages are detected, timed and logged automatically.
Demo only — in the app these change your real Powerwall settings.
Everything your solar home has been missing
Real math from your own Tesla readings — not guesses, not generic averages.
Cars that charge themselves on sunshine
- ✓Automatic charging follows spare solar every 2 minutes
- ✓Backs off the moment the house pulls from the grid
- ✓Never-below floor keeps every commute covered
- ✓Start/stop and charge-limit sliders, like the Tesla app
Powerwall control & outage readiness
- ✓Backup reserve and battery mode from one popup
- ✓Off-grid and Bunker 100% emergency console
- ✓Tesla Storm Watch with live weather alerts
- ✓Grid outages detected, timed and logged
A daily plan in plain English
- ✓Morning briefing from Watson, your curious advisor
- ✓Peak Defense shield for the 4–9 PM window
- ✓Evening wrap: what happened vs. the plan
- ✓Household text everyone can actually follow
Honest costs, real savings
- ✓Every car kWh split into sun, Powerwall and grid
- ✓Priced hour by hour at your real time-of-use rate
- ✓Supercharger costs synced; away charging auto-logged
- ✓Monthly charging budget per car
Bill audit that checks PG&E's math
- ✓Upload a bill — delivery and generation split out
- ✓Peak, partial-peak and off-peak reconciliation
- ✓Rate trends: see which charge keeps rising
- ✓Next-bill prediction locked in, not shifting daily
Upgrade advice with real payback
- ✓Battery, more panels, carport, second charger, ADU
- ✓Gas-to-EV swap: fuel plus maintenance savings
- ✓Spots sun you send to the grid and suggests an EV
- ✓Enter real installer quotes and compare bids
Tips Watson proves with your real numbers
- ✓Free tactics: 2-car sun shuttle, pre-cooling, appliance timing
- ✓Tap "I'm trying this" and Watson measures it
- ✓Before vs. after from your own meter, after 7 days
- ✓Predictions get sharper as real results come in
Plus family sharing — everyone in the house sees the app, only you change the settings.
Start free. Upgrade when it clicks.
One plan, one price. 7-day free trial.
- •Tesla + Powerwall sync
- •Today's hourly solar curve
- •Tomorrow's headline & 7-day outlook
- •7 days of history
- •Weekly Watson household text
- ✓Everything in Free
- ✓Automatic solar car charging
- ✓Powerwall & emergency controls
- ✓Live power-flow view
- ✓Daily briefing, Peak Defense & evening wrap
- ✓Real charging costs & budgets
- ✓Bill audit, rate trends & bill prediction
- ✓Upgrade advisor with installer quotes
- ✓Savings tips measured against your real bill
- ✓Unlimited history & family sharing
Where WhatSun fits
Tesla runs your hardware. WhatSun decides what it should do today — and only takes the wheel where you let it. Turn on automatic charging and your cars soak up spare sun on their own; leave it off and you still get a clear daily plan. No homelab, no rules to write, no second system to babysit.
And Watson stays curious. He keeps hunting for free ways to save — like swapping two cars so one charges on sun while the other commutes — then checks your real numbers a week later to prove what actually worked.
Built in California, for NEM 3.0 and time-of-use homes, by an owner running two solar arrays, three Powerwalls, and two EVs.
Ready for tomorrow morning?
Set up your system in 5 minutes. Get your first plan tomorrow at sunrise.