Most people come to this question after a storm. The power’s been out for two days, the fridge is starting to smell, and someone in the house is saying “we need a generator.” That’s usually when I get the calls. And honestly? It’s not a bad time to think about it, because nothing clarifies your priorities faster than sitting in the dark.

But here’s what I want you to understand before we get into the numbers: solar panels and generators are solving slightly different problems, and the backup power conversation involves trade-offs that most installers will gloss over because they’re only selling you one of the two options. I’m not selling either. So let me give you the honest version.

What You’re Actually Comparing

When people say “solar for backup,” they almost always mean a solar-plus-battery system. Panels alone don’t give you backup power during an outage. (This surprises a lot of people. I’ve had homeowners call me frustrated, saying their solar system went dead during a grid outage, even though the sun was shining. That’s a safety feature, not a malfunction. Grid-tied inverters shut down automatically so utility workers aren’t electrocuted by your panels feeding power back into downed lines.) So the real comparison is: solar + battery storage vs. a standalone generator.

Those are genuinely different animals. A generator is a fuel-burning engine. A solar-battery system is an energy storage device that gets recharged by sunlight. Both can keep your lights on when the grid goes down. The similarities stop there pretty quickly.

The Cost Picture (And Why It’s Complicated)

Recommended Emporia Vue Gen 2 Home Energy Monitor 16 Sensors

Real-time whole-home electricity monitor with 16 circuit sensors and solar/net metering capability.

Check Price →

Helpful resource: Jackery SolarSaga 100W Solar Panel is a top-rated option for this. (As an Amazon Associate this site earns from qualifying purchases.)

Let me put some real numbers on the table, because the range here is enormous and the vagueness in most articles is unhelpful.

OptionUpfront CostAnnual Operating CostLifespanFuel Dependency
Portable generator (3,500-7,500W)$500 - $2,000$150-$400 (fuel + maintenance)10-15 yearsYes (gasoline)
Standby generator (7,000-22,000W)$3,500 - $12,000 installed$200-$500 (maintenance + fuel)15-20 yearsYes (propane/natural gas)
Solar + 1 battery (e.g., Tesla Powerwall 3)$12,000 - $18,000 after federal tax creditNear-zero (monitoring, occasional service)25-30 years panels / 10-15 years batteryNo
Solar + 2 batteries$18,000 - $28,000 after creditNear-zeroSameNo

A few things to flag in that table. The federal Investment Tax Credit (ITC) is currently 30%, which knocks a meaningful chunk off the solar side. As of July 2026, that credit is still intact, though its long-term status has been subject to political debate, so I won’t pretend it’s guaranteed forever. The generator costs also assume you’re using it only occasionally. If you’re running a portable generator for hours every week, fuel costs add up fast at $4-5/gallon.

The standby generator installed cost is the one that catches people off guard. A 22kW Generac Guardian, which is a popular whole-home option, runs about $5,000-$7,000 for the unit alone, then you’re paying an electrician and possibly a gas line extension on top of that. I’ve seen installations come in over $15,000 for larger homes with complicated setups.

What Each One Actually Does Well

Related video

What Type of Solar Panel Should You Buy? · The Solar Lab on YouTube

Here’s where I’m going to be a little contrarian, because the solar industry loves to sell batteries as a total replacement for generators, and that’s often oversimplified.

Generators genuinely shine when:

You need a lot of power for a long time. A whole-home standby generator running on a natural gas line has effectively unlimited runtime. If you’re in an area that loses power for days or weeks (think ice storms in the Southeast, or extended grid failures in rural areas), a generator connected to the gas line keeps going as long as gas is flowing to your neighborhood. A solar battery system, by contrast, is a finite tank. A single Tesla Powerwall 3 holds 13.5 kWh. The average American home uses about 29 kWh per day according to EIA data. You do the math. Two batteries gets you closer, but a string of cloudy winter days can still drain them.

I tested this mentally with a family I consulted for outside Asheville, North Carolina. They’d lost power for five days during a winter storm. They had a south-facing roof with good solar potential, but their loads were heavy and they had a well pump. I told them honestly: one battery won’t cut it for five-day outages in December. A standby generator on propane made more sense for their situation, even though I’m a solar person.

Solar plus battery wins when:

Your outages are short and frequent, you care about not worrying about fuel, you want to run essential loads quietly (batteries are silent), and you’re also interested in reducing your electricity bill the rest of the time. That last point is the real kicker. A generator does absolutely nothing for your electric bill on a normal Tuesday. A solar-battery system does. EnergySage’s market data shows that homeowners with solar systems save an average of $1,500 per year on electricity, depending on their location and utility rates. That’s real money that partially offsets the higher upfront cost.

The other genuine advantage: no fuel logistics. I’ve talked to people who had a generator and ran out of gas at midnight during a storm because they couldn’t get to a station. That’s a real failure mode. Batteries recharge from the sun, and on a decent solar day, even a single Powerwall can get meaningfully recharged.

The Reliability Question Nobody Asks Out Loud

You might be wondering: which one actually works when I need it? And the honest answer is: both can fail, just in different ways.

Generators require maintenance. Oil changes, carburetor cleaning on portable units, load-testing standby units monthly. A generator that sits for six months and then gets called on during an emergency has a real chance of not starting. I’ve heard this story more times than I can count. Ethanol-blended gasoline gums up carburetors. Propane standby units need annual servicing.

Solar-battery systems have their own failure modes. Inverters fail. Battery cells degrade over time. And if your system isn’t properly configured with a critical load panel or a whole-home backup inverter, it may only power a subset of your circuits during an outage. The installation quality matters enormously here. A poorly installed battery system can fail to kick in when the grid goes down, which is exactly the worst moment to discover that.

The Solar Energy Industries Association has documented significant growth in paired solar-storage installations, which tells us the market is maturing, but it also means there are more inexperienced installers entering the space. Get references. Ask specifically how the system will behave during a grid outage.

The “Both” Answer (And When It Makes Sense)

Some of the most prepared homeowners I know have both. A solar-battery system handles the frequent short outages and reduces the daily electricity bill. A smaller generator sits in the garage as a backup for extended emergencies. This isn’t wasteful if you live in a hurricane or ice storm zone. A modest 3,500W portable generator ($700-$1,000 from Honda or Champion) plus a solar-battery system gives you genuine resilience without spending $20,000 on a massive battery bank.

Scenario: A homeowner in coastal Texas, 2,200 sq ft home, with an 8kW solar array and one Powerwall 3, decides to keep a Honda EU3200i portable inverter generator for hurricane season. Total additional cost: about $1,100. Result: she covered 95% of her power needs on solar all year, and the generator gave her peace of mind for the one or two annual events where extended outages were plausible.

If you want to track your energy use and figure out exactly what loads matter most during an outage, a home energy monitor like the Emporia Vue can tell you which appliances are eating your battery capacity. (The site may earn a commission on purchases.) That data changes how you think about battery sizing.

Sources

Disclosure: As an Amazon Associate, we earn a small commission from qualifying purchases at no extra cost to you. We only recommend products that genuinely support the topics covered in this article.