Is a Home Battery Worth It in 2026? Sizing and Payback

For most households, a home battery pays for itself slowly, if at all, from bill savings alone. It is most worth it when you need backup power through outages, when your utility pays little for the solar power you send to the grid, or when your rate plan charges much more in the evening than overnight. Since January 1, 2026 there is no federal tax credit for a battery you buy yourself; the 30% Section 25D credit ended for installations completed after December 31, 2025.

The Two Jobs a Battery Does

Backup power. When the grid goes down, a battery with the right inverter keeps chosen circuits running: refrigerator, lights, internet, a well or sump pump, medical equipment. This value is real but doesn't show up as a bill saving.
Bill savings by time-shifting. The battery charges from solar at midday or from the grid when power is cheap, and you use that energy when power is expensive. The saving per kWh is the gap between the two prices, minus some energy lost in charging and discharging.

Why Your Utility's Export Rules Matter

If your utility credits exported solar at the full retail rate (classic net metering), the grid already acts like a free battery, and a real one adds little bill saving. If exports are credited at less than retail, storing midday solar and using it yourself in the evening is worth more.

California is the best-known example. Customers who applied to connect solar on or after April 15, 2023 are on the state's Net Billing Tariff, which credits exports at their value to the grid. The California Public Utilities Commission says that value is usually lower than the retail rate, and that pairing solar with a battery is how customers get the most bill savings under it. Rules differ by state and utility, so read your own utility's current tariff before running numbers.

Worked Example

Part 1, sizing for outages. These are the defaults in our Home Battery Backup calculator. Essential loads: refrigerator 150 W × 8 h, LED lights 60 W × 5 h, router 15 W × 24 h, device charging 40 W × 4 h, well or sump pump 800 W × 1 h, window AC or space heater 1,500 W × 1 h. That totals 1,200 + 300 + 360 + 160 + 800 + 1,500 = 4,320 Wh (4.32 kWh) a day.

One 13.5 kWh battery at 95% depth of discharge and 94% inverter efficiency gives 13.5 × 0.95 × 0.94 = 12.06 kWh usable. 12.06 ÷ 4.32 = 2.79 days (about 67 hours). A 3-day target needs 4.32 × 3 = 12.96 kWh, so 2 batteries.

Part 2, payback from bill savings. Suppose a quote of $15,000 installed for one battery, and you shift 10 kWh a day from a $0.20 higher evening price to a cheaper period. Savings: 10 × 365 × $0.20 = $730 a year. Payback: $15,000 ÷ $730 = 20.5 years.

Under the old 30% credit the same battery would have cost $10,500 after tax, for a payback of $10,500 ÷ $730 = 14.4 years. Compare either figure with the warranty years on your quote. A payback longer than the warranty means the battery is mostly a backup purchase, not an investment.

What Moves the Answer

Factor	Makes a battery more worth it when
Outage frequency	Outages are frequent or long, or someone at home depends on powered medical equipment.
Rate plan	Evening prices are much higher than overnight or midday prices.
Export credit	Your utility pays well below retail for exported solar.
Local incentives	A state or utility program pays toward the battery or for letting the utility draw on it at peak times.
Loads you back up	You back up essentials only. Whole-house backup with central air takes several batteries.

Solar Alone Won't Keep Your Lights On

Grid-tied solar inverters shut off automatically when the grid goes down, so line workers aren't exposed to power from your roof. Solar only recharges a battery during an outage if the battery and inverter are designed for backup (islanding) operation. If outage backup is your main reason for buying, confirm this in writing with the installer.

Questions to Ask the Installer

Which circuits will it back up, and for how long with my actual loads?
Can the solar recharge the battery during an outage?
What does the warranty cover, in years and in total energy cycled, and what capacity is guaranteed at the end?
Which state or utility programs apply, and who files the paperwork?

What This Doesn't Cover

This guide doesn't cover battery chemistry, battery wear over years of cycling, financing costs, whole-home generators, or leased and third-party-owned systems. The payback example uses assumed prices and ignores round-trip energy losses, which lengthen payback a little. Have a licensed electrician or solar installer size the battery, inverter and critical-loads panel for your home.

Home Battery Backup Calculator

List your essential loads and see how many days one battery lasts.

Solar Payback Calculator

Run the solar side first if you are pairing the two.

Sources

IRS: Residential Clean Energy Credit (battery storage of 3 kWh or more; not available after 2025)
IRS: FAQs on the One, Big, Beautiful Bill energy credit changes (expenditure made when installation is completed)
California Public Utilities Commission: Net Energy Metering and Net Billing