Incentives · Utility rate programs

TOU Battery Savings Calculator

On a time-of-use (TOU) rate, electricity costs more in the late afternoon and evening than overnight or midday. A battery can charge when power is cheap and run your home when it is expensive. Enter your ZIP to load a researched plan from your utility, or type in your own prices, and see what that shift is worth: day by day, month by month, and against what the battery costs.

Savings per year—
Total—
Cost recovered—
Payback—

A day on this plan

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    Savings by month

    Year one. Most plans pay off in summer, when the gap between peak and off-peak prices is widest.

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    Savings toward the battery’s cost

    Running total, with any VPP earnings you entered stacked on top.

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    What moves your number

    Change in total TOU savings if one assumption changes and everything else stays the same.

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    Your battery on every researched plan

    Same battery and home, run through each utility’s published prices. Your plan is highlighted; plans in your state are darker.

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    Plan prices used

    Check these against your bill. TOU prices change often, sometimes monthly.

      Batteries aren’t the only way to shift

      On the same TOU plan, EV charging, water heaters, and heat pumps can also move their use to cheaper hours, often for less money than a battery. See Drive Economics for EV charging on TOU rates and Heatpump Economics for heating and cooling costs.

      How this estimate works

      • Daily cycleOn each day with a peak, the battery runs the home through the peak window, up to the smaller of your home’s use, the battery’s output, and the stored energy above your backup reserve. It recharges once in the cheapest hours.
      • Savings per kWhPeak price avoided, minus the cost of recharging that kWh plus round-trip losses. If that is negative in a season, the battery is left idle then.
      • Leftover energyWhere a plan has a mid-priced period (for example, Hawaii’s overnight rate), leftover energy offsets it when that still beats losses.
      • DaysAbout 250 weekdays and 115 weekend days and holidays a year. Summer home use applies May–September.
      • Not includedExporting battery power to the grid, demand charges, taxes, fixed monthly charges, backup value, and incentives. Totals are not discounted.

      This is a planning estimate, not a bill guarantee. Utility prices and plan rules change; confirm your plan’s current prices and battery eligibility before buying. Battery Economics has no affiliation with any manufacturer or utility. For the research behind these plans, see Case Study 01: What a home battery saves on time-of-use rates.