The Home Battery ReportIndependent · No installer money

Savant Power Storage 20 vs Tesla Powerwall 3

A straight, side by side read on specs and warranties, with the honest caveats. Every figure is from the manufacturer datasheet; sources are at the bottom.

Figure - Specs to scalebars vs the largest in our database
Savant Power Storage 20 versus Tesla Powerwall 3: specs to scaleHorizontal bars comparing usable capacity, continuous power, peak power, warranty for Savant Power Storage 20 and Tesla Powerwall 3, each scaled against the largest value in the home battery database.Savant Power Storage 20Tesla Powerwall 3Usable capacity18 kWh13.5 kWhContinuous power12.5 kW11.5 kWPeak power30 kWNot publishedWarranty10 yr10 yr
SpecSavant Power Storage 20Tesla Powerwall 3
ChemistryLiFePO4Not published
Usable capacity18 kWh13.5 kWh
Continuous power12.5 kW11.5 kW
Peak power30 kWNot published
Round-trip efficiency93.8%89%
Warranty10 years, warrantied to 73 MWh or 3,650 cycles, with an estimated 75 percent capacity retention at 10 years10 years
Backup scopeWhole-home capableWhole-home capable
InverterIntegratedIntegrated

What actually differs

  • More usable capacity: the Savant Power Storage 20 offers 18 kWh vs 13.5 kWh, so at that size it carries more of your home for longer per charge.
  • More continuous power: the Savant Power Storage 20 sustains 12.5 kW vs 11.5 kW, which matters for running big loads like an AC at once.
  • Efficiency is not apples to apples here: the Savant Power Storage 20 quotes 93.8% (Round trip efficiency per the Savant Power Storage 20 specification sheet) and the Tesla Powerwall 3 quotes 89% (solar round trip (solar to battery to home), CEC weighted; not a pure AC to AC figure), so do not read the raw numbers as a direct ranking.

Which one pays off is a numbers question.

Neither spec sheet tells you the payback in your home. That comes from your rate plan and incentives.

Run the Worth It calculator →

Sources

Source: Savant Power Storage 20 Specification Sheet (009-2477-00). Specs verified 2026-07-01. Figures are per single unit at beginning of life; confirm the current datasheet with your installer.

Source: Tesla Powerwall 3 datasheet, 2026. Specs verified 2026-07-01. Figures are per single unit at beginning of life; confirm the current datasheet with your installer.