Can Rooftop Solar Keep My Lights On During a Power Outage?

Usually not. Many homeowners are surprised to learn that most rooftop solar systems automatically shut down when the electric grid loses power. Unless your system includes battery storage (or another approved backup power source), your solar panels will typically stop producing usable electricity during an outage—even on a bright sunny day.

Why Does Solar Shut Down?

This surprises many people because it seems intuitive that solar panels should continue producing electricity whenever the sun is shining. The reason is safety.

A typical rooftop solar system is connected directly to the electric grid. During a power outage, utility workers may be repairing damaged power lines. If solar systems continued sending electricity into those lines, they could create a serious safety hazard. To prevent this, grid-connected solar inverters are designed to automatically disconnect when they detect that the grid has gone down.

Think of it like a safety switch: No grid = No solar power to your home.

What Does a Battery Change?

A battery changes everything. A properly designed battery system can disconnect your home from the utility grid while allowing your solar panels to continue powering your home and recharging the battery. Instead of shutting everything off, your home essentially becomes its own small electrical system.

During an extended outage:

• Solar powers your home whenever possible.
• Excess daytime production charges the battery.
• The battery supplies electricity overnight or during cloudy periods.
• If the battery becomes depleted before enough new solar energy is available, your home may temporarily lose power until solar production recovers.

Does a Battery Mean Unlimited Backup Power?

No. A battery doesn't create electricity—it stores it. Your home's ability to remain powered depends on three things working together:

• How much electricity your home uses
• How much solar energy your roof produces
• How much energy your battery can store

That question recognizes that your battery isn't simply running down. Every day, your solar panels may recharge it, allowing your home to continue operating far longer than the battery alone could support.

Daily Self-Powered Resilience

This is the way Sunbank evaluates backup performance. Rather than relying on simple rules of thumb, Sunbank evaluates your home's energy performance hour by hour, taking into account:

• Your home's hourly electricity usage
• Expected solar production throughout the day
• Battery charging and discharging
• Seasonal weather patterns
• Extended outage scenarios

The result is an estimate of your home's daily self-powered resilience—the number of hours each day your home is expected to meet its normal electricity needs without power from the utility grid during an extended outage.

For many homeowners, that answer changes significantly throughout the year. For example, a system that can power an entire home around the clock during a mild spring week may only provide partial-day coverage during a hot Gulf Coast summer, when air conditioning demand is much higher.

That's why Sunbank evaluates resilience seasonally, helping you understand not only how your system performs under ideal conditions, but also during the times of year when reliable backup power matters most.

The Bottom Line

Rooftop solar alone typically will not keep your home powered during an outage. Adding battery storage can dramatically improve your home's resilience, but backup performance depends on much more than battery capacity alone.

Understanding how your home, your solar array, and your battery work together over time provides a much clearer picture of what you can expect during a prolonged outage—and helps you choose a system that matches your family's needs.