Tesla Powerwall Calculator

Enter your electricity bill and Powerwall count — get installed cost, 30% ITC savings, backup hours, TOU arbitrage, and payback period.

Your electricity profile

Monthly electricity bill?

State?

Utility rate?

$/kWh

Time-of-Use (TOU) pricing

TOU pricing plan?

Disabled

Powerwall configuration

Existing solar system?

Number of Powerwalls?

Backup priority?

Tesla Powerwall system estimate

1 × Powerwall 3 — 13.5 kWh total

Total installed cost$18,000

ITC 30% federal tax credit-$5,400

Net cost after ITC$12,600

Continuous power output7.6 kW

Backup hours (essential loads)9.0 hrs

Est. annual savings$270/yr

Payback period46.7 yrs

10-year net savings-$9,900

Link copied to clipboard

How to Use This Calculator

Enter your electricity profile

Start with your average monthly electricity bill and select your state — the calculator pre-fills the state's average utility rate. Override the rate with your actual $/kWh from your bill for the most accurate results. Your bill amount determines how much energy you use annually, which drives the savings calculation.

Enable TOU pricing if applicable

Time-of-Use plans charge more during peak hours (typically 4–9pm weekdays) and significantly less overnight. If your utility offers TOU, enabling this toggle unlocks the arbitrage savings calculation — Powerwall charges at the cheap off-peak rate and discharges during expensive peak hours. California PG&E and SDG&E, Arizona APS, and Texas TXU all offer TOU plans well-suited to Powerwall.

Choose your Powerwall count and backup priority

Select 1–4 Powerwalls and whether you want to back up essential loads only (lights, fridge, router, phone — about 1.5 kW) or your whole home (including HVAC and appliances — about 5 kW average). The backup hours output reflects your actual priority choice. If you have existing solar, enter those kilowatts to see how Powerwall improves self-consumption.

The Formula

Total Capacity = Powerwalls × 13.5 kWh Total Cost = Powerwalls × $18,000 (installed mid-point) Net Cost = Total Cost × (1 − 0.30 ITC) Backup Hours = Total kWh ÷ Load kW TOU Arbitrage = kWh × 0.90 efficiency × (Peak Rate − Off-Peak Rate) × 365 Self-Consumption Increase = 40% base + 8% per additional unit (max 60%) Payback = Net Cost ÷ Annual Savings 10-yr Net Savings = Annual Savings × 10 − Net Cost

The ITC (Investment Tax Credit) at 30% applies when Powerwall is installed with solar or charged 100% from solar. The TOU arbitrage savings assume one full charge/discharge cycle daily at 90% round-trip efficiency. Self-consumption increase estimates how much more of your solar you'll use directly versus exporting to the grid at lower buyback rates.

Example

Sarah — 2 Powerwalls with solar in California

Sarah has a $200/month bill, 8 kW of solar, and is on PG&E's TOU-C plan ($0.45 peak, $0.15 off-peak). She wants whole-home backup and max TOU savings.

Monthly bill$200/mo ($0.27/kWh)

Existing solar8 kW

Powerwalls2 (27 kWh total)

TOU rates$0.45 peak / $0.15 off-peak

Backup priorityWhole home

Result

Total installed cost$36,000

ITC 30% credit-$10,800

Net cost$25,200

Whole-home backup~5.4 hrs

TOU arbitrage/yr~$2,180/yr

Solar self-consumption increase+48%

Payback period~7.9 yrs

Two Powerwalls give Sarah 5.4 hours of whole-home backup and over $2,000/year in TOU arbitrage savings — on top of higher solar self-consumption. The 30% ITC brings the net cost to $25,200, with payback under 8 years on a system backed by a 10-year Tesla warranty.

FAQ

How much does a Tesla Powerwall cost installed in 2025? ▼

The Tesla Powerwall 3 costs $16,000–$20,000 installed per unit, depending on your state, installer, and any electrical panel upgrades required. Tesla installs directly in many markets, or through their certified installer network. The federal ITC reduces this by 30% when paired with solar — bringing a single unit to $11,200–$14,000 net. Multiple units share some installation costs, so 2+ units cost less per unit than one alone.

How long will a Tesla Powerwall power my home during an outage? ▼

One Powerwall (13.5 kWh) powers essential loads (lights, fridge, router, phone — ~1.5 kW) for 8–9 hours. Running a whole home at average draw (~5 kW including AC) depletes it in about 2.7 hours. Two Powerwalls extend essential backup to 18 hours; three to 27 hours. With paired solar, the Powerwall recharges during the day — effectively providing indefinite backup for essential loads in sunny weather. Tesla's Storm Watch feature automatically maximizes charge before severe weather.

Can I get the 30% tax credit on Powerwall without solar? ▼

Starting January 1, 2023, the IRA updated the ITC so standalone battery storage qualifies for the 30% federal tax credit regardless of whether it's paired with solar. Previously, the battery had to be charged by solar to qualify. This means a Powerwall installed on its own still gets the 30% credit — on the battery unit cost, not on any grid charging costs. Consult your tax advisor, as the credit is non-refundable (it reduces tax liability but won't result in a refund if you owe less than the credit amount).

Is Powerwall worth it without solar panels? ▼

Without solar, Powerwall's financial case relies entirely on TOU arbitrage — charging cheap overnight, discharging during expensive peak hours. In high-rate states with strong TOU plans (California, Massachusetts, New York), this can save $800–$1,800/year per unit, with payback of 10–15 years. The non-financial value — backup during outages — is significant in storm-prone areas (Florida, Texas, Southeast). If your area has reliable power and flat-rate electricity, Powerwall without solar is hard to justify financially.

What's the difference between Powerwall 2 and Powerwall 3? ▼

The Powerwall 3 (released 2024) is a major upgrade: it integrates a solar inverter directly into the unit, eliminating the need for a separate solar inverter. Capacity is the same at 13.5 kWh, but continuous power increases from 5 kW (PW2) to 7.6 kW and peak power reaches 22 kW. The built-in inverter supports up to 20 kW of solar DC input. This means a new solar + Powerwall 3 system uses fewer components and can be installed more neatly. Existing Powerwall 2 units with gateway are still supported with firmware updates through 2030+.

Related Calculators

Embed This Calculator

Free to embed on your website. Just copy this code:

<iframe src="https://solarsizecalculator.com/tesla-powerwall-calculator"
  width="100%" height="700" frameborder="0"
  title="Tesla Powerwall Calculator"></iframe>