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More homeowners across the US are installing solar panels because they want greater energy independence and have more control over their energy bills... but it also raises an important question:
If the power goes out, will my solar panels keep working?
A home can only rely on their solar panels during a blackout if they have batteries. This often comes as a surprise to many homeowners. But it’s important to realize that this isn’t a flaw in solar technology. It's an important safety feature, and there are ways to design a system that can still provide power during an outage.
This guide explains what really happens when the grid goes down, why solar systems shut off, how batteries and backup power work, and what you can realistically expect from modern solar technology.
Will my solar panels work in a power outage?
On their own, no. Solar panels will only work during a power outage if you have the correct battery setup.
If your home has a standard grid-tied solar panel system without a battery, it will automatically shut down during a power outage. Your lights will go out, your appliances will stop working, and your home will lose power just like other homes in your neighborhood, even if the sun is shining.
This applies to solar installations of all sizes and ages. Unless your system has the right equipment to provide backup power, it will not supply electricity to your home during an outage.
Why do solar panels turn off during a power outage?
It might seem strange. Your solar panels are generating electricity right on your roof, so why can't your home keep using that power when the grid goes down?
The answer comes down to safety requirements designed to protect homeowners and utility workers repairing the power lines. During an outage, utility workers may be repairing power lines they believe are de-energized. If solar systems continued feeding electricity into the grid, those lines could unexpectedly become live, creating a risk of serious injury or electrocution.
To prevent this, your solar inverter monitors the grid's voltage and frequency. If it detects a loss of grid power or conditions outside the permitted range, it automatically disconnects the system from the grid. Without suitable backup equipment, your home can no longer use the electricity your panels generate.
In the US, grid-connected solar installations must meet electrical safety standards, which require them to disconnect from the grid during a power outage. This safety feature is known as anti-islanding. Standards such as IEEE 1547-2018 set requirements for how these systems respond to grid disturbances.
This is a mandatory safety requirement. It’s not an optional setting that installers can just switch off.
Does this mean solar panels are useless during a power outage?
With the right equipment, solar panels can still be useful during power outages.
Solar panel installations on their own are not designed to work during a power outage. To keep some or all of your home powered, you typically need a solar battery, a backup-capable inverter, and the right electrical setup. Some systems can provide limited backup power without a battery, but this depends on the equipment.
Different types of solar setups
To understand your options, it helps to look at the different ways solar systems can be set up:
Off-grid systems
Off-grid solar systems aren't connected to the utility grid. They're most common in places where connecting to the grid is difficult or expensive. You’ll often find off-grid systems in cabins, farms, and rural properties in remote locations.
Many of these systems use solar panels to generate electricity and have batteries to store it for later use. An inverter converts the stored electricity into power your home can use. As the name says, off-grid systems don't rely on the grid. But they still need a reliable way to supply power when the solar panels aren't generating enough electricity. And this usually means having batteries.
Off-grid living offers energy independence, but it requires enough battery storage and careful energy management to cover periods of low sunlight. For most US homes, staying connected to the grid is more practical and cost-effective.
Standard grid-tied solar systems
This is the most common type of residential solar setup in the US.
In a grid-tied system:
- Solar panels generate electricity during daylight hours.
- Your home uses the solar power it needs.
- Excess electricity may be sent to the grid.
- The utility grid supplies power when your panels aren't generating enough.
This setup helps reduce electricity bills while keeping your home connected to the grid.
Without a battery, standard systems shut down during a power outage for safety reasons. This means your panels won't power your home unless you have backup equipment.
Solar with battery storage and backup power
Many people choose to install modern solar installations to include a battery. Batteries let you use more of your own solar power in the evening and overnight.
The battery stores excess solar energy instead of sending it all to the grid. This reduces your reliance on utility electricity and can also lower your energy bills.
But it’s important to understand that not all batteries will provide power during an outage.
For backup power to work, the system must also include:
- A hybrid or battery-compatible inverter
- A backup power function
- Additional wiring to supply selected circuits or, in some systems, the whole home during an outage
When configured correctly, this setup allows your home to disconnect safely from the grid and continue operating as a self-contained power system.
What is islanding or backup mode?
When a power outage occurs, a properly configured solar and battery system with backup capability follows a controlled process.
First, the inverter detects the loss of grid power and activates a switch that disconnects your home from the utility grid. This prevents electricity from flowing back into power lines while utility workers carry out repairs.
Once disconnected, the system switches to island mode, allowing your home to run on electricity from your battery and, when available, your solar panels.
The transition can happen almost instantly, but it depends on the equipment. Some systems provide backup power immediately, while others may cause a brief interruption in your power supply.
With a battery, what can you run during an outage?
Backup power is designed to keep essential appliances and systems running, not to replicate your home's normal electricity use.
Most systems are set up to supply electricity to a dedicated circuit for essential loads. This might include:
- Lighting in key rooms
- Refrigerators and freezers
- Wi-Fi routers and phone chargers
- Medical devices and mobility equipment
High-power appliances are often excluded, such as:
- Electric ovens and cooktops
- Electric water heaters
- Heat pumps
- EV chargers
This is because of the limited capacity of the battery and backup system.
Understanding battery limits
Home batteries can store a useful amount of energy, but their capacity is limited.
Many residential batteries in the US provide around 10–20 kilowatt-hours (kWh) of usable storage. According to the US Energy Information Administration (EIA), the average US household uses roughly 28–29 kWh of electricity per day, depending on the home's size, location, and heating and cooling needs.
Batteries have limits on how much power they can deliver at once. Some systems provide around 3–5 kilowatts (kW) of continuous power, while others can deliver a lot more. An electric range can draw several kilowatts, so running it alongside other appliances could overload a smaller system or quickly drain the battery.
For this reason, it's best to be selective when using backup power during an outage. With careful energy management, a battery can keep essential appliances running for hours or longer. And if your solar panels can continue generating electricity during the outage, they may also help recharge the battery and extend your backup supply.
Do all home batteries include backup power as standard?
No, not all home batteries will include backup power. This is an important detail for homeowners to understand.
Some battery systems are designed primarily to store energy for later use and help lower electricity bills. Having a battery doesn't automatically mean your home will have power during an outage. The system must be designed and installed to provide backup power.
Depending on the equipment, backup power may require:
- Additional hardware to disconnect your home safely from the utility grid.
- Extra wiring or a separate panel for backed-up circuits.
- An inverter designed to support backup power.
- Careful system design to determine which appliances can run during an outage.
These requirements can add to the installation cost. Before choosing a system, discuss your backup power needs with your installer and confirm exactly which parts of your home will remain powered during an outage.
How do I know if my solar and battery system is safe?
The US Department of Energy's guide to solar permitting and inspection explains how local permits, safety inspections, and utility approval help ensure rooftop solar systems are installed safely and connected to the grid properly.
How Switch Together can help
Switch Together is a group buying program that helps homeowners install solar panels and home batteries at competitive prices. We connect residents with vetted installers and help them explore their options for backup power.
Through the program, homeowners can:
- Learn about home battery and backup power options
- Understand what their system can realistically power during an outage
- Explore systems designed to meet their household needs
- Make informed decisions with no obligation to proceed
If backup power and peace of mind are important to you, then get in touch with Switch Together. Visit our solar website, here.
Key takeaways
For most US homes, solar panels alone won't provide power during an outage. This is a safety feature that protects utility workers and the electrical grid.
With the right solar panels, battery, and backup equipment, you can keep essential appliances running during an outage, even if you can't power your entire home as usual.
Understanding how solar backup works can help you decide whether it's worth investing in for your home.
