Find out how many Powerwall 3 units your home needs. Enter your energy usage and backup goal for instant sizing, cost estimates, and solar savings.
Based on Tesla Powerwall 3 specs: 13.5 kWh usable capacity, 11.5 kW continuous output, 95% round-trip efficiency.
Your Energy Usage
kWh/day
$
Bills include taxes and fees, so this gives a conservative estimate.
$
/kWh
kW
h/day
Your Powerwall System
—
Powerwalls
—
Backup Duration
at your avg load
—
Estimated Cost
—
Battery Savings
System Layout
Cost Breakdown
Solar + Powerwall Savings
Powerwall 3 Specifications
Usable Capacity
13.5 kWh
Continuous Power
11.5 kW AC
Peak Power
20 kW (DC input)
Round-Trip Efficiency
95%
AC Output
120/240V split-phase (US)
Max System Size
4 units (54 kWh)
Dimensions
43.5" × 24" × 7.6" (1105 × 609 × 193 mm)
Weight
291.2 lbs (132 kg)
Operating Temp
-4°F to 122°F (-20°C to 50°C)
Warranty
10 years, 70% capacity retention, unlimited cycles
Mounting
Wall or floor mount, indoor/outdoor rated
Frequently Asked Questions
How many Tesla Powerwalls do I need for my house?
Most US homes use about 30 kWh/day. Without solar, one full day of backup requires roughly 3 Powerwall 3 units. With solar panels that recharge the batteries during the day, 2 units often suffice since the battery only needs to cover nighttime usage. Use the calculator above to get an exact number based on your energy usage and solar setup.
How much does a Tesla Powerwall 3 cost installed?
A single Powerwall 3 costs approximately $9,200 for the unit, plus $1,100 for the Tesla Gateway and $4,500–$7,000 for installation. Total installed cost is typically $14,800–$17,300 for one unit. The federal 30% ITC expired at the end of 2025, but some state and local incentives may still be available — check DSIRE for your area.
Can one Powerwall run a whole house?
A single Powerwall 3 provides 13.5 kWh of usable storage and 11.5 kW of continuous power. For the average US home (30 kWh/day), one unit provides about 10–11 hours of backup. It can run essential loads (fridge, lights, router, phone charging) for much longer, but a full day of whole-home backup typically requires 2 units.
Is the Powerwall worth it without solar panels?
Without solar, a Powerwall provides backup power during grid outages but offers minimal financial savings. It can also save money through time-of-use arbitrage if your utility has peak/off-peak rates. Pairing with solar panels maximizes both energy independence and savings. Check your state and local programs for available incentives.
How long does a Tesla Powerwall last?
Tesla warrants the Powerwall for 10 years with at least 70% capacity retention and unlimited cycles. In practice, LFP-based batteries like the Powerwall 3 typically last 15–20 years with proper use. The unit is rated for indoor or outdoor installation and operates in temperatures from -4°F to 122°F.
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