Generator vs Battery Backup: Which Is Right for Your Home?
The best backup option depends on the outages you actually face. For short, occasional outages, a home battery or even a portable power station is quiet, clean and low-maintenance. For long, multi-day outages from hurricanes, ice storms or wildfire shutoffs, a standby generator running on natural gas or propane is hard to beat for sheer runtime. Many homes are best served by the cheapest option that covers their essential loads, not the biggest system a salesperson can fit.
The three main options
| Standby generator | Home battery | Portable power station | |
|---|---|---|---|
| What it is | Permanently installed engine generator with automatic transfer switch | Wall- or ground-mounted battery with backup gateway | Portable battery box with built-in outlets |
| Fuel | Natural gas or propane | Stored electricity, recharged by solar or grid | Stored electricity, recharged by wall outlet, car or portable solar panels |
| Runtime | As long as fuel lasts | Until stored energy runs out (longer with solar) | Hours to a day or two on small loads |
| Switching | Automatic, usually within seconds | Automatic, often near-seamless | Manual: you plug things in |
| Noise and emissions | Engine noise, exhaust | Silent, none on site | Silent, none on site |
| Maintenance | Oil changes, regular self-test runs, annual service | Very little; software updates | Very little |
| Bill savings | None | Possible in some areas | None |
| Typical cost | Varies widely; get local quotes | About $12,000–$16,500 for 13.5 kWh installed | Hundreds to a few thousand dollars |
What about cost?
Battery pricing is well documented: about $1,130 per kWh installed as of October 2026, per EnergySage, or roughly $12,000 to $16,500 for a typical 13.5 kWh unit. Owned batteries get no federal tax credit for 2026 installs.
Standby generator prices vary too much for us to give a reliable national figure. The total depends on generator size, whether you need a new gas line or propane tank, the transfer switch, electrical work, permits and a concrete pad. Whole-home units can land in the same general range as a battery once everything is included, and smaller essential-circuit units cost less. Get at least two itemized local quotes.
Portable power stations and portable generators are the low-cost options, typically in the hundreds to low thousands of dollars.
Start with your outage profile
Before comparing equipment, look at your actual outage history. Your utility may publish reliability data, and your own memory of the last few years is a good guide.
Short and occasional (a few hours, a few times a year). A battery or a portable power station is usually enough. A standby generator is probably overkill.
Frequent short outages. A battery shines here. It switches over automatically and silently and doesn’t need to start an engine every time.
Long, multi-day outages (hurricanes, ice storms, wildfire safety shutoffs). A battery alone may run out, especially in winter or during storms when solar output is low. A standby generator on natural gas or a large propane tank, or a battery plus generator combination, provides the most reliable long runtime.
Medical needs. If someone depends on powered medical equipment, plan for redundancy. A portable power station dedicated to the device is a sensible baseline, whatever else you choose. Also register with your utility’s medical baseline or critical-care program if one exists.
How long will a battery last in an outage?
It depends on the loads. Here’s a rough guide for a 13.5 kWh battery. Your appliances will differ, so check their labels or use an energy monitor.
| Scenario | What’s running | Approximate runtime |
|---|---|---|
| Essentials only | Refrigerator, some lights, internet, phone charging, a few outlets | A day or more |
| Essentials plus gas furnace fan | Above, plus furnace blower in winter | Around a day, depending on how often the furnace runs |
| Whole home with central AC in summer | Everything, including AC | Often just hours |
| Electric heat or electric water heater | Large heating loads | Hours |
With solar panels connected and a sunny day, the battery can recharge, extending runtime a lot. On cloudy days, in winter or after a storm with snow-covered panels, recharge may be minimal. Plan for the worst week, not the best.
Our battery calculator can estimate runtime for the loads you choose.
Continuous power matters too
A battery’s kWh decides how long it lasts. Its continuous kW decides what can run at once. A battery rated for 5 kW can’t run a central AC, an electric range and a well pump together. Air conditioners and well pumps also need a surge of power to start. Check the battery’s surge rating against your equipment. Our best home batteries guide compares these specs.
Fuel: the generator’s strength and weakness
Natural gas generators run as long as gas keeps flowing, which is usually through electric outages. That’s their big advantage. In rare cases, such as earthquakes or extreme cold, gas service can also be disrupted.
Propane runs as long as your tank lasts. A larger tank means more runtime. Ask your installer to estimate days of runtime at your expected load.
Gasoline (portable generators) is the least convenient. You need to store fuel safely, and stored gasoline degrades over time unless treated. During widespread outages, gas stations may also lose power.
Batteries need no fuel delivery, but their “tank” is small and refills only from solar or the grid.
Maintenance and reliability
Standby generators need regular care: oil and filter changes, a periodic automatic exercise run to stay ready, and an annual service. A generator that hasn’t been maintained may not start when you need it.
Batteries need almost nothing beyond software updates. Capacity slowly fades over time; warranties typically guarantee 60% to 70% of original capacity at the end of a 10- to 15-year term.
Portable power stations need occasional charging during storage and slowly lose capacity with age.
Safety
- Carbon monoxide is the big generator risk. Never run a portable generator indoors, in a garage, or near windows, doors or vents. Install battery-powered CO alarms.
- Backfeeding is dangerous. Never plug a generator into a household outlet to power the house. Use a properly installed transfer switch or interlock so you can’t send power onto utility lines.
- Batteries should be installed to code by a qualified installer. LFP chemistry, now dominant in home batteries, is generally considered safer than older NMC chemistry.
What about solar without a battery?
Standard grid-tied solar shuts off when the grid goes down. This is a safety feature, so your system can’t energize lines that crews are repairing. That surprises many owners after their first outage.
A few inverters offer limited daytime backup without a battery:
- Enphase IQ8 microinverters can provide “Sunlight Backup” during daylight with the right system controller.
- SMA Sunny Boy inverters have a Secure Power Supply outlet that gives limited power when the sun is out.
These help with daytime charging and small loads, but they stop at sunset and dip with every cloud. More in off-grid vs grid-tied.
Combining a battery and a generator
Some systems are built to work together:
- FranklinWH aGate acts as a whole-home transfer switch and can integrate a generator.
- Generac PWRcell integrates with Generac standby generators.
The battery covers short outages quietly. During a long outage, the generator runs for a few hours to recharge the battery or carry heavy loads, then shuts off. This uses less fuel and gives the widest coverage, but it means buying both.
The cheapest options worth considering first
If your goal is getting through occasional outages, not cutting bills, start small:
- A portable power station sized for your fridge, lights, internet and phones. Some can recharge from portable solar panels.
- A portable generator with a transfer switch or interlock installed by an electrician, for longer outages.
- Efficiency upgrades that make any backup last longer, like an efficient refrigerator or LED lighting. See efficiency before solar.
We list some lower-cost options on our recommended page. We earn a small, disclosed commission on some of those links; see how we make money.
Bottom line: Buy a home battery for backup if you’d value silent, automatic, low-maintenance protection, or if it also saves money under your rates. Buy a standby generator if long outages are your main worry. And if outages are rare and short, a portable power station may be all you need.
Questions to ask before you buy
- Which circuits will be backed up, and what is their combined running and starting power?
- How many hours or days will the system last at my expected load, in winter and summer?
- For a generator: what size gas line or propane tank is needed, and what does maintenance cost each year?
- For a battery: what are the warranty’s years, throughput and end-of-warranty capacity?
- Does the quote include the transfer switch or gateway, permits and any panel upgrade?
If a battery is part of a solar quote, compare it with and without the battery in compare options, and read do solar batteries pay off? to see whether it also earns its keep on your bill.
Common questions
Will my solar panels work during a power outage?
Not on their own. Standard grid-tied systems shut down automatically when the grid goes out, so they can't send power onto lines utility crews are working on. You need a battery, or a specific inverter feature like Enphase's Sunlight Backup or SMA's Secure Power Supply outlet, to use solar during an outage.
How long will a home battery run my house?
It depends on what you run. A 13.5 kWh battery could keep a refrigerator, lights, internet and a few outlets going for a day or more, but central air conditioning or electric heat can drain it in hours. With solar recharging it on sunny days, essential loads can sometimes run indefinitely.
Is it safe to run a portable generator in the garage?
No. Generators produce carbon monoxide, which can kill. Run portable generators outdoors only, far from doors, windows and vents, and use battery-powered carbon monoxide alarms inside the home. Never connect a generator to house wiring without a proper transfer switch or interlock.
Can I have both a generator and a battery?
Yes. Some battery systems, like FranklinWH's aGate and Generac's PWRcell, are designed to integrate a generator. The battery handles short outages silently, and the generator recharges it or carries the load during long ones. It costs more but covers the widest range of outages.
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