Choose a small battery (roughly 5–10 kWh) if you only need to keep a fridge, lights, internet and phones running. Choose a mid-size battery (roughly 10–20 kWh) if you also want a well pump, a few outlets or a freezer. Choose multiple batteries and a larger inverter only if you want air conditioning or electric heat during an outage. Backup power is priced by what you run and for how long, not by the size of your solar array.
In 2026, published installed prices for home batteries mostly fall between about $700 and $1,300 per usable kilowatt-hour (kWh), and some quotes run higher. A single 10–15 kWh battery commonly lands somewhere between $9,000 and $18,000 installed. Adding solar panels on top raises the total considerably. This guide breaks down where the money goes, how to size a system for backup, what changed with incentives, and which mistakes make quotes balloon.
Last updated: October 2026. Prices are U.S.-market ranges in USD and vary by region, installer and equipment.
Key takeaways
- Grid-tied solar panels alone generally shut off during an outage. A battery (or a specially configured inverter) is what keeps your home powered.
- Cost per kWh is a useful comparison number, but sizing for your actual outage loads comes first.
- The battery is usually about half to two-thirds of the installed price. Installation, inverter, backup panel and permits make up the rest.
- The federal 30% residential clean energy credit (Section 25D) no longer applies to systems installed after December 31, 2025. State, utility and local programs vary.
- Quotes for the same job can differ widely. Compare at least three, line by line.
Try it: which backup setup fits you?
One question, an instant answer, and a link to the section that matters most for you. Nothing you choose is stored or sent anywhere.
During a multi-day outage, what do you need to keep running?
Estimate only. This is a starting point for conversations with installers, not a design.
How solar plus battery backup works
Most home solar systems are grid-tied: they feed the home and the utility together. For safety, a standard grid-tied inverter switches off when the grid goes down, so utility line workers are not exposed to power coming back from your roof. That is why many people with solar panels still sit in the dark during outages.
A battery changes that. When the grid fails, a transfer device disconnects your home from the utility (called islanding), and the battery and inverter power your chosen circuits. If your panels are connected to a compatible inverter, they can recharge the battery during the day, which is what turns a few hours of backup into days.
Two terms show up in quotes and are worth knowing early:
- Usable capacity (kWh): the energy you can actually draw, which is the number to compare. Total capacity can be higher.
- Continuous power (kW): how much the system can supply at once. A big battery with a small inverter still cannot start a large motor or run several heavy loads together.
Where the money goes
Published 2026 guides disagree on exact numbers, which is itself useful information: pricing depends heavily on brand, region, installer and how complex the electrical work is. Across sources, a reasonable planning range is roughly $700–$1,300 per usable kWh installed, with premium or low-volume setups costing more. Treat any single number you read, including these, as a starting range to verify with local quotes.
| Cost component | What it covers | What changes the price |
|---|---|---|
| Battery | Cells, battery management system, enclosure. Often roughly half to two-thirds of the installed price. | Usable kWh, chemistry, brand, warranty |
| Inverter and power electronics | Converts power and sets how much you can run at once. May be built into the battery or separate. | Continuous kW, whether your existing inverter is compatible |
| Backup panel or transfer equipment | Separates the circuits you want powered in an outage from everything else. | Number of backed-up circuits, main panel age and capacity |
| Labor, permits, inspection | Electrician time, utility interconnection, local approvals. | Local labor rates, permitting rules, install location |
| Solar panels (if new) | Panels, racking, wiring, rooftop work. | System size in watts, roof complexity, local market |
For panels, one 2026 market summary put typical residential pricing at roughly $2.50–$3.15 per watt before incentives, with regional differences. Compare proposals by price per watt rather than total price, since larger systems always cost more in total.
Installing solar and a battery in the same project can save money. You pay for permitting, design and site visits once, and the equipment is chosen to work together from the start. Adding a battery to an existing system can still make sense, but check inverter compatibility first.
Size the battery before you price it
The most common reason people overspend is starting with a battery model and working backward. Work in the other direction.
- List what you would miss. Refrigerator, a few lights, router, phone chargers, laptop, medical equipment, a well pump, a freezer. Skip the electric dryer, oven, pool pump and central air for now.
- Estimate daily energy use for that list. Look at appliance labels or a plug-in watt meter. A modern refrigerator, LED lighting, internet equipment and device charging together often land in the low single-digit kWh per day, but your numbers may differ.
- Pick your target duration. A few hours to overnight is a very different purchase from three days without sun.
- Check peak power. Motors (well pumps, compressors, air conditioners) draw a surge when they start. Ask installers to confirm the system can handle it.
- Divide. Rough runtime in hours is usable kWh divided by your average load in kW.
Illustrative example (not real data): if your essential circuits average 0.3 kW, a 10 kWh battery would in theory cover about 33 hours without any solar recharge. With sun recharging it during the day, the same battery could stretch much further. Run the same math with a 4 kW central air conditioner and the battery empties in a couple of hours, which is why air conditioning drives costs so sharply.
Ask each installer to state in writing which circuits are backed up and for how many hours, with and without sunshine.
Cost by setup: a comparison
The ranges below are illustrative estimates built from the published per-kWh range above and typical capacity needs. They are not quotes, and local prices can fall outside them.
| Setup | Typical battery size | Illustrative battery cost (installed) | What it usually runs |
|---|---|---|---|
| Essentials | About 5–10 kWh | About $6,000–$14,000 | Fridge, lights, internet, device charging |
| Extended | About 10–20 kWh | About $10,000–$25,000 | Essentials plus well pump, freezer, home office |
| Whole home | 20 kWh and up, high-output inverter | About $20,000–$40,000 or more | Most circuits, possibly air conditioning or electric heat |
Add solar panels to any row and the total rises by the cost of the array. As an illustration, an 8 kW system at the per-watt range above would be roughly $20,000–$25,000 before incentives, on top of the battery.
Smaller batteries tend to cost more per kWh than larger ones, and a second battery unit is often cheaper per kWh than the first because installation work is shared. So a cheap-looking per-kWh number on a big battery does not mean it is the right purchase if you only need a small one. Right-size first, then compare per-kWh prices within that size.
Three ways to buy: pros, cons and who each suits
New solar plus battery together
- Pros: one permit and design process, equipment chosen to match, easier to optimize for backup.
- Cons: the highest total outlay, and a long payback if backup is your only goal.
- Not a fit if: your roof is heavily shaded or you only need a few hours of backup.
Battery added to existing solar
- Pros: you keep your panels and pay only for storage and the electrical work.
- Cons: older inverters may not work with a battery, which can add cost, and some systems need rewiring or an extra inverter.
- Not a fit if: your current system is near the end of its life, since you may be better off planning an upgrade.
Battery only, no solar
- Pros: the lowest cost of entry, and it can charge from the grid.
- Cons: it cannot recharge during a long outage, so it is a short-duration solution.
- Not a fit if: your area has multi-day outages and you need ongoing power.
Incentives in 2026
The biggest change for buyers is on the federal side. The Residential Clean Energy Credit under Section 25D gave a 30% credit for solar and battery storage (3 kWh minimum). Under the One Big Beautiful Bill Act, signed July 4, 2025, it does not apply to expenditures after December 31, 2025. Projects placed in service by that date can still be claimed on a 2025 return using IRS Form 5695, and unused credit can carry forward.
That means a system installed in 2026 should be priced without assuming the 30% credit. Be cautious with any salesperson who quotes a "after tax credit" price without explaining which rule applies. Third-party ownership arrangements such as leases and power purchase agreements may follow different tax rules, so ask for the terms in writing and consult a tax professional about your situation.
Other help varies by location. Some states, utilities and local programs offer storage rebates or paid backup-battery programs; California's Self-Generation Incentive Program (SGIP) is one well-known example. Check your utility's website and your state energy office for what is currently open, because funding runs out and rules change.
Costly mistakes to avoid
- Sizing for the whole house by default. Backing up every circuit can double the cost. A well-chosen essentials panel often delivers most of the benefit.
- Ignoring peak power. A battery with plenty of kWh but low kW may fail to start a pump or air conditioner.
- Comparing only per-kWh price. A cheap large battery is no bargain if you needed a small one, and a low-priced quote may leave out the backup panel or electrical upgrades.
- Skipping the inverter question. Ask whether your current inverter works with the battery, and what happens to your panels in an outage.
- Counting on a tax credit that no longer applies. See the incentives section above.
- Overlooking the main panel. An old or full electrical panel may need upgrading, which is a separate line item.
- Not reading the warranty. Check the covered years, cycle limits and the retained-capacity guarantee, since a battery loses capacity over time.
- Forgetting your outage reality. If outages usually last two hours, you may be paying for days of capacity you will rarely use.
Best for...
- Short outages and tight budgets: a small battery on essential circuits.
- Existing solar owners: a battery retrofit, after confirming inverter compatibility.
- Frequent multi-day outages: solar plus battery with enough panel capacity to recharge daily.
- Medical equipment or remote work: a reliable essentials setup, with a professional load review. A battery may be only one layer; discuss backup plans with the equipment provider or a clinician.
- High-use homes with air conditioning: multiple batteries, a larger inverter and a realistic budget, or a plan to back up only select zones.
Questions readers ask
Will solar panels alone power my house in an outage?
Usually not. Standard grid-tied systems shut down when the grid does. You need a battery, or an inverter specifically designed to supply power during an outage, and a way to separate your home from the grid.
Can I add a battery later?
Often yes, but compatibility matters. Some systems are designed for easy battery additions, while others require inverter changes. Ask your installer whether the equipment is "battery-ready" if you want to phase the project.
How long will a battery last in an outage?
Usable kWh divided by your average load in kW gives a rough runtime without recharging. With solar, daytime generation can refill the battery, so the real answer depends on weather, panel size and how much you run.
Is a generator cheaper?
A portable or standby generator usually costs less upfront, but it needs fuel and maintenance and produces noise and exhaust. Batteries run silently, can work daily to reduce bills in some markets, and recharge from solar. The right choice depends on outage length and your priorities. Always run generators outdoors and away from windows.
Is a battery worth it if outages are rare?
That is a personal call. If backup is the only goal and outages are rare, the payback can be long. Value depends on your utility's rate structure, any incentives and how much an outage would cost you, which is hard for a general article to judge.
Our recommendation by situation
- Mostly short outages, limited budget: start with a small battery on essential circuits.
- Already have solar: get a retrofit quote, and confirm inverter and panel compatibility before comparing prices.
- Long outages are normal where you live: prioritize solar plus battery sized to recharge daily, and consider a generator as a second layer.
- Want everything backed up: price a whole-home system and an essentials system side by side, then decide whether the difference is worth it.
- Not sure: list your essential loads, collect at least three itemized quotes, and ask each installer to state runtime in writing.
Prices, incentives and equipment change quickly, so confirm current figures with licensed local installers and your utility. For decisions that depend on your taxes or home wiring, consult a qualified tax professional or electrician.