Home battery backup without solar: Is it worth it?

If you've lived through a multi-day power outage, you already know the cost of being unprepared. Spoiled food, no heat or AC, a sump pump that can't do its job—the list goes on. As storm season ramps up each year, many homeowners are shopping for backup power before the first blackout hits.

Generators have traditionally been the go-to option, but they’re noisy, run on fossil fuel, and need regular maintenance. Battery backup systems offer a quieter, cleaner, lower-maintenance alternative, and what many people don’t realize is that you don’t need solar panels to install one.

A standalone home battery charges from your outlets like any other appliance, then holds that charge until you need it. When the power goes out, it kicks in automatically. You can say goodbye to generator fumes, long extension cords, and last-minute trips to the gas station for fuel.

That said, a battery without solar has real limits worth understanding before you commit, especially around how long it can run your home during a prolonged outage.

A home battery is a large rechargeable unit—typically wall-mounted in your garage or utility room—that stores electricity and releases it on demand. The most popular models on the market today include the Tesla Powerwall, Enphase IQ Battery, and FranklinWH aPower2.

Most residential batteries store between 10 and 20 kilowatt-hours (kWh) of electricity per unit. To give you a sense of scale: the average U.S. household uses about 29 kWh per day, according to the U.S. Energy Information Administration. That means a single battery won't keep your entire home up and running as usual for an entire day, but it can power just the essentials for one to three days, depending what you plug into it.

When you install a battery without solar panels, it charges directly from the grid, the same way your house always draws power. The battery then stores some of that power to have on standby for when the grid goes down. Think of it like a bigger version of a portable charging bank you might carry for your cell phone.

In nearly every scenario, it’s makes the most sense to pair a home battery with solar panels. But there are a few legitimate reasons a homeowner might want a battery on its own.

Battery costs have dropped considerably in the last decade, but they’re still a big investment. The average home battery installation costs $15,650 for 13.5 kilowatt-hours (kWh) of storage—the amount most homes need to keep essential devices running during outages.

There’s good news: You may qualify for home storage incentives that can bring the price down. The federal investment tax credit (ITC) for batteries expired in 2025, but some states and utilities offer additional rebates, tax credits, or programs—like enrolling in a virtual power plant (VPP)—that can increase your overall savings.

The payback period for a standalone battery is harder to calculate than for solar because its primary benefit is insurance-style protection rather than direct savings. If you're mainly buying for outage backup, you're paying for peace of mind. If you're also using it for TOU arbitrage, your utility bills will tell you fairly quickly whether it's paying off.

This is where a lot of homeowners get surprised. A 13.5 kWh battery (the capacity of a single Tesla Powerwall 3) may sound like a lot, but what it can power depends entirely on what devices you want to power and how much power those devices require

We’ve calculated how long a 13.5 kWh battery would run the average home by region, using monthly (EIA) data.

How long a 13.5 kWh battery will run your house, by region

Not sure which region your state is in? Check out the chart.

Note: The average energy used per day is estimated based on annual averages, but energy use fluctuates by season, which will affect how long your battery will last.

If you're running only essential loads—a refrigerator, Wi-Fi, a phone charger and a few lights—you might get two, maybe three days during the outage. If you tack on major appliances—like a central air conditioner, a heat pump, or an electric water heater—that time drops significantly. For example, a 5-ton central AC unit can draw 3.5 kW or more when running, which means a fully charged single battery could be drained in four hours of continuous use.

Most battery installers will work with you on what’s called a critical loads panel—a separate electrical subpanel that connects only your essential circuits to the battery. This lets you be strategic about which appliances will use power from your battery rather than trying to run your whole home through it. Even then, if you need whole-home backup or extended power for several days, you'll likely need multiple batteries. Some homeowners in high-outage-risk areas install two or three units.

A standalone battery is useful on its own, but the real benefit comes when you add solar panels. A grid-tied battery without solar is, effectively, a one-time reserve. Once it's empty, you're waiting for the grid to come back on like everyone else.

Add solar panels, and your battery charges every day the sun comes out. Suddenly a multi-day outage becomes much more manageable.

Beyond storm resilience, solar improves the financial case. The average homeowner who goes solar through EnergySage saves more than $61,000 on electricity over 25 years—some up to $155,000— with most systems paying for themselves for themselves within a decade.

A standalone battery won't generate those kinds of returns because it doesn't produce energy, it just stores it. Pairing the two means your system can produce electricity and protect you from rate fluctuations and power outages, which is why the two work better together than either does alone.

If adding solar right now isn't in the cards right now, that's a valid decision. Just know that most modern batteries are designed to pair with solar panels down the road, so you're not locking yourself out of that option later.

The right battery for your home comes down to a few questions:

• How much backup capacity do you want?

• What appliances/devices do you need to power?

• Are solar panels in your future?

If your main goal is protecting essentials during an outage, a single 10–13.5 kWh battery is usually enough. If you want to keep more of your home running or need coverage for multiple consecutive days, plan for two or more units.

If you think you might eventually add solar, you should choose a battery that's solar-compatible from the start rather than buying equipment you'll need to replace later. A reputable installer will walk you through that tradeoff.

The most useful thing you can do before committing is get a few quotes. Battery pricing varies more than most people expect, and what an installer proposes for your specific home matters more than a national average. EnergySage's Marketplace makes it easy to compare quotes from pre-vetted installers in your area, whether you're looking at battery-only or battery-plus-solar. Our Energy Advisors can also help you think through which setup actually makes sense for your situation at no cost to you.