Solar Battery Storage in 2026: Cost, Payback and Whether It Is Worth It

A home battery does two jobs: it keeps the lights on when the grid goes down, and it can lower your bill by storing solar power for later. In 2026 the federal credit that covered 30% of the cost is gone, so it is worth being clear about which job you are paying for.

What batteries cost in 2026

The Powerwall 3 is about 13% below the marketplace average and held 61% of EnergySage marketplace share in the second half of 2025. It stores 13.5 kWh, delivers up to 11.5 kW continuously, and has a built-in inverter.

The huge per-kWh range shows why you should compare quotes on price per kWh of usable storage, not just the total.

The tax credit is gone

The residential clean energy credit, which covered 30% of battery costs, does not apply to expenditures after December 31, 2025. Some pages, including a few installer and review sites, still show "net cost after the 30% credit." For a 2026 purchase, that math is wrong. Check your state and utility for programs that remain.

Job 1: backup power

A battery keeps essential circuits running during an outage, silently and without fuel. How long it lasts depends on what you run. Low-power essentials such as the refrigerator, lights, internet and a gas furnace's blower can run far longer than central air conditioning or an electric range.

Continuous output matters as much as storage. A battery rated at 11.5 kW continuous can run more at once than a smaller unit, even with the same kWh.

Backup makes the most sense if:

• Outages are frequent or long where you live
• Someone in the home relies on powered medical equipment
• You have a well pump or sump pump that must keep running
• A standby generator is impractical or not allowed

Job 2: lowering your bill

A battery can store solar power produced at midday and use it in the evening, when electricity is often priced higher under time-of-use rates.

This matters most under net billing, where utilities credit exported solar power at a low rate. California's net billing tariff, often called NEM 3.0, credits exports well below the retail price, so storing your own solar power is worth more than sending it to the grid. Under traditional net metering, where exports earn close to retail, a battery adds much less bill savings.

Some utilities also run virtual power plant programs that pay battery owners to share stored power during peak demand. Terms vary widely, so check your utility's current program.

How big a battery do you need?

Start with what you want to power, not the battery size:

• Essentials only (refrigerator, lights, internet, furnace fan, a few outlets): one battery around 13.5 kWh is a common starting point.
• Whole-home backup including central air, an electric range or a well pump: usually more storage and higher continuous output, often two or more units.
• Bill savings only: size to the evening energy you use after the sun sets, which your installer can estimate from your utility data.

Ask your installer to show which circuits the battery will back up and roughly how many hours it can run them.

Battery or generator?

Many homeowners in areas with long outages pair solar and a battery for daily use with a generator for rare multi-day events.

Warranties and lifespan

Battery warranties are measured in years and remaining capacity. Tesla's Powerwall warranty is 10 years, and some competitors, such as FranklinWH and Enphase, advertise 15-year warranties, according to a 2026 installer comparison. Read the warranty document itself for capacity retention terms, throughput limits and any requirement to keep the battery connected to the internet.

Is it worth it for you?

Probably yes if:

• You face frequent or long outages
• Your utility uses net billing with low export credits
• Time-of-use rates create a big gap between daytime and evening prices
• State, utility or virtual power plant incentives lower the cost

Probably not if:

• Outages are rare and short
• You have full retail net metering
• You are buying mainly for bill savings without incentives
• A portable or standby generator meets your backup needs for less

Before you buy

1. Decide whether backup or bill savings is your main goal
2. List the circuits you want to back up
3. Compare quotes on price per usable kWh and continuous kW
4. Confirm the warranty terms in writing
5. Make sure the quote does not subtract a federal credit

Installation details to check

Batteries are usually mounted in a garage, on an exterior wall or in a utility area, following the manufacturer's clearance and temperature rules. Most jobs need an electrical permit and inspection, and some homes need panel changes to add backup circuits. Ask the installer to include permits, any panel work and utility interconnection paperwork in the quote.

If you do not have solar yet, start with whether solar is worth it in 2026, and before signing, read how to vet a solar installer. Batteries may also require panel work; see electrical panel upgrade.