SolarNerdz
SolarNerdz Home Energy Playground
A straight, nerdzy answer on solar panels, electric cars, and home batteries
Play with a roof, a real EPA car list, and a battery — then, if you want, leave an email. Enter your address, miles, and electric bill to see what solar can do.
Totally free to you. Play, estimate, get quotes, leave an email — homeowners pay $0
Gas you stop buying
$2,520/year
Starts selected: 2026 Tesla Model Y Standard AWD · 462 gal you do not buy vs your car at 26 mpg. Premium $/gal starts at $5.46 (US default — enter a ZIP for the nearest metro EIA premium series). Edit in the playground.
House-only solar
$2,070/yr
Bill savings, house only
Driving
$2,760/yr
$2,520 gas you skip
House + electric car
$4,830/yr
Solar bill + driving
Total: 25 solar panels
House 19 solar panels · Electric car 6 solar panels · Battery 0 solar panels
1 · Roof
Your address and your electric bill
City + ZIP is enough — try Grand Junction, CO or 81501. Street is optional.
Type a city or ZIP (try Grand Junction or 80205) to drop a pin. Until then we use U.S. average sun.
Paired with yearly kWh at about $0.16/kWh for U.S. average sun. Move either slider — the other follows.
This yearly use sizes the array at the sun for your pin. The monthly bill is the paired dollar input.
Advanced — roof guess and $/W
Optional. If you change these, the array is sized from the roof guess instead of the bill. You do not need them for a first estimate.
Living area ÷ stories × 1.12 pitch, unless you override.
Typical one-face guess. Roof hold: 35 solar panels.
Starts at $2.75/W. Honest band about $2.25–$3.25/W ($17,100–$24,700 before incentives).
Your house
Your house needs 19 solar panels
400 W each · 7.6 kW
About 14,250 kWh/year at this sun, versus roughly 10,500 kWh for the house — this array is sized to cover that yearly use.
Mid installed cost $20,900 (range $17,100–$24,700)
2 · Electric car
The new gas station, where you leave the house each day with a full tank
Gas you stop buying
$2,520/year
2026 Tesla Model Y Standard AWD · 462 gal vs your car at 26 mpg
National average until you enter your ZIP. Slide to adjust it however you like.
$5.46
467 electric cars a US shopper can buy new now (EPA 2025–2026). Future certified years and older lots are hidden. Showing 40 of 467 matches.
Selected 2026 Tesla Model Y Standard AWD · 265 Wh/mi · 6 solar panels for these miles. Maker site
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Each 400 W solar panel here is estimated at 570 kWh/year at this location. Switch cars — the solar panel count should jump. More Wh/mi means more solar panels.
Solar panels needed to drive your miles
Your electric car needs 6 more solar panels400 W each · 2.4 kW · 3,180 kWh/yr
2026 Tesla Model Y Standard AWD at 265 Wh/mi. A thirstier car needs more roof.
3,180 kWh of those miles are already on the array.
12,000 miles/year in this estimate.
House 10,500 kWh · electric car 3,180 kWh. The car is a slice of the house, not a second house.
Enter MPG for the car you drive now. Starts at 26 mpg.
3 · Free Car!
How solar can earn you a free car
17.3 years of net driving savings = a free 2026 Tesla Model Y Standard AWD and free solar panels to power it
The first 2.8 years pay off the 6 solar panels for your car. The next 14.5 years of your net driving savings pays for the car.
Year-1 driving math
What the electric car adds
Gas not bought
$2,520
462 gal · $5.46/gal · 26 mpg
Shop work skipped
+$240
Oil changes and typical upkeep you stop paying for
Extra grid charging
−$0.00
0 kWh the roof does not cover
Net year-1 add
$2,760
$2,520 + $240 − $0.00 = $2,760
Gas not bought plus shop work skipped, minus extra grid charging — folded into year-1, payback, Free Car!, and 25-year totals.
4 · Battery
What a battery does for you
Moves midday sun into the evening — and through an outage.
Tesla Powerwall 3 · 13.5 kWh suggested
No extra solar panels needed; it charges from the solar panels above.
When the utility is out
Peace of mind when the utility power goes out
When the grid goes down, the battery keeps your lights, fridge, internet, and other essentials running. The solar panels recharge it the next day.
Estimate: about 13.5 hours of essentials
13.5 kWh usable ÷ about 1 kW of essential load (lights, fridge, internet). Outage-time estimate only — not a dollar value.
Optional — peak vs off-peak
5 · Investment
The investment
Year-1 savings split
House, battery, and electric car.
- House19 solar panels · 45%$2,248
- Electric car6 solar panels · 55% · Free Car! ~year 17.3$2,760
- Solar panelsHouse + electric car + battery25 solar panels
- TOTAL SAVINGS$5,008
Estimated investment
$28,700
Year-1 savings
$5,008
Together estimate
5.7 yrs
25 solar panels
Optional — inflation assumptions
6 · Quote
Get a solar quote
Leave your email. Nearby solar companies may contact you to quote.
This estimate
Total: 25 solar panels
House 19 solar panels · Electric car 6 solar panels · Battery 0 solar panels