See how much a home battery saves by storing cheap off-peak (or solar) energy and discharging during expensive peak time-of-use hours. Calculate daily and annual energy-arbitrage savings, account for round-trip losses, and find your battery's payback period.
Peak-shaving & arbitrage savings
Many U.S. utilities now charge time-of-use (TOU) rates — electricity costs far more during peak evening hours than overnight. A home battery (like a Tesla Powerwall, Enphase, or LG unit) lets you store cheap energy — either from your solar panels or low-cost off-peak grid power — and discharge it during expensive peak hours, shaving the priciest kilowatt-hours off your bill. This is called energy arbitrage or peak shaving.
The savings per cycle equal the peak energy you avoid buying, minus the cost (and round-trip losses) of charging the battery. Because batteries are only about 85–95% efficient, you need to store a bit more than you get back. With a 13.5 kWh battery cycled once daily, a $0.45 peak vs $0.12 off-peak spread can save several hundred dollars a year. This calculator factors in usable depth of discharge, round-trip efficiency, and your local rates to show daily savings, annual savings, and how long the battery takes to pay for itself.
The bigger the rate spread, the more a battery saves. Steep TOU plans make storage far more valuable.
Batteries return ~85–95% of stored energy. The calculator accounts for the energy lost charging.
Charging from your own solar at near-zero cost maximizes the spread and the savings.
The federal residential clean-energy credit and state/utility rebates cut battery cost and shorten payback.
As more American utilities roll out time-of-use (TOU) pricing, "is a Tesla Powerwall worth it," "home battery payback," and "solar battery savings calculator" have become top searches for U.S. homeowners. A home battery stores cheap off-peak or solar energy and discharges it during expensive peak hours, shaving the priciest kilowatt-hours off your bill. This calculator quantifies that energy arbitrage — daily savings, annual savings, and how long the battery takes to pay for itself.
Savings depend on your peak-to-off-peak price gap, round-trip efficiency, and how often you cycle. In high-rate states like California (and on steep TOU plans elsewhere), a battery paired with solar and the 30% federal residential clean-energy credit can deliver a compelling payback. Enter your real rates to see if it pencils out.
A 13.5 kWh battery cycled once daily on a plan with a $0.45 peak and $0.12 off-peak rate (90% efficiency) saves roughly $1,560 per year by discharging during peak hours. Against an $11,000 installed cost after incentives, the payback is about 7 years — shorter where the peak/off-peak spread is bigger.
U.S. homeowners with solar panels or time-of-use electricity plans evaluating a home battery (Tesla Powerwall, Enphase, LG) for energy arbitrage, peak shaving, and backup power.