Will solar panels power the house during an FPL outage?
A conventional grid-connected solar system normally stops supplying power when the grid fails. FPL requires customer-owned generation to isolate automatically from the grid during an outage to prevent dangerous backfeed to restoration personnel.
Backup operation needs a system designed to operate safely while isolated. Depending on the configuration, that can include a battery, compatible inverter, control equipment, and a defined set of supported circuits. Ask the installer exactly which circuits operate during an outage and what commissioning test will demonstrate that behavior.
FPL notes that a net-metering customer may operate renewable generation during a grid outage if appropriate equipment—such as a specialized inverter or battery system—is installed. A grid connection is still required for a customer who wants to participate in net metering.
Battery kW and kWh solve different problems
Kilowatts (kW) measure power delivered at a moment. Kilowatt-hours (kWh) measure energy available over time. A backup design needs enough power for appliances operating together and enough energy for the desired duration.
For example, two hypothetical batteries may each have 10 kWh available, but one may support 3 kW continuously while the other supports 7 kW. Their duration budget can be similar at the same average load, while their ability to start or run appliances simultaneously is different.
Motor startup adds another constraint. An air conditioner or pump can briefly demand more power than it uses once running. The selected equipment, controls, and appliance specifications—not only battery capacity—determine whether a specific appliance can operate.
Published battery capacity is only a starting point
Manufacturer specifications help frame a comparison, but the installed proposal still needs to address controls, electrical work, permits, communications, mounting, compatible solar equipment, and the circuits that receive backup. Availability and configuration vary.
Published manufacturer figures; verify the offered model and configured system with the selected installer before signing.
| Battery model | Published energy capacity | Published continuous power |
|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | 11.5 kW in Tesla’s published U.S. configuration |
| Enphase IQ Battery 5P | 5.0 kWh usable | 3.84 kW |
| Enphase IQ Battery 10C | 10 kWh usable | 7.08 kW (manufacturer announcement/specification) |
- Adding expansion capacity can increase energy without increasing power in the same proportion.
- A manufacturer battery page is not a property-specific runtime quote.
Calculate battery runtime for your home
A first-pass calculation is: estimated runtime in hours = energy available to supported loads in kWh ÷ average supported load in kW. It is a planning check, not an outcome guarantee.
Assume, for illustration only, that a commissioned system can deliver 10.8 kWh to backed-up loads at the start of an outage. The table excludes solar recharge, battery condition, temperature, conversion losses, standby consumption, and cycling appliances.
Arithmetic illustration only; not a manufacturer runtime claim or property-specific forecast.
| Average supported load | Calculated runtime from 10.8 kWh |
|---|---|
| 0.3 kW | 36 hours |
| 0.5 kW | 21.6 hours |
| 1.0 kW | 10.8 hours |
| 3.0 kW | 3.6 hours |
Build an essential-load budget before selecting equipment
List each appliance, its measured or documented power use, and the hours it operates. For cycling equipment such as a refrigerator, use daily consumption or an average that includes its on-and-off cycle. Watts × hours ÷ 1,000 = kWh.
Invented daily-load worksheet. Replace every input with information for your household and equipment.
| Supported load | Assumed average draw | Hours per day | Daily energy |
|---|---|---|---|
| Refrigerator with cycling included | 80 W | 24 | 1.92 kWh |
| Router and modem | 15 W | 24 | 0.36 kWh |
| Selected LED lights | 30 W | 5 | 0.15 kWh |
| One efficient fan | 40 W | 10 | 0.40 kWh |
| Phone and device charging | 60 W | 2 | 0.12 kWh |
| Total | Varies | Varies | 2.95 kWh |
- A powered modem and router do not guarantee internet service if the provider’s external network is down.
- Pumps, kitchen appliances, extra refrigerators, EV charging, and entertainment devices can materially change the total.
Can a battery run central air conditioning?
A suitable battery system can support some central air conditioners when the design satisfies running power, startup requirements, and desired runtime. The review must use the actual cooling equipment and simultaneous household loads.
For illustration, an assumed 3 kW air-conditioner load running six hours consumes 18 kWh. Adding the invented 2.95 kWh essential-load worksheet makes 20.95 kWh per day—well above a 10.8 kWh planning budget before considering losses or other loads.
Ask the installer to evaluate compressor startup demand, inverter output, any soft-start or load-control equipment, and what other large appliances may operate at the same time. A whole-home label does not replace an energy budget.
Solar recharge during an outage and existing-system compatibility
A compatible system can recharge from solar in backup mode, subject to configuration and operating conditions. Clouds, shading, storm conditions, and household demand affect the energy available to recharge. Storage also has conversion and retrieval losses.
Use a conservative production scenario. If backed-up demand is 6 kWh in a day and compatible solar contributes 4 kWh to those loads, the remaining 2 kWh shortfall must come from stored energy before additional losses. Ask what happens after the battery reaches its minimum operating level and how recovery works.
An existing solar system needs a compatibility assessment. Bring inverter and panel models, original design, interconnection documents, utility details, and monitoring information. If the array has an active production concern, resolve or assess that issue before treating the battery design as complete.
Evaluate backup value and commission before storm season
Compare a solar-only proposal with a solar-plus-storage proposal on the same load and utility assumptions. Request the incremental installed battery price, additional annual bill savings, supported circuits, and expected outage operation. Backup value may be the central reason to buy storage even where incremental bill savings are limited.
The IRS states the Residential Clean Energy Credit is not available for property placed in service after December 31, 2025. Do not deduct a personal 30% federal credit from a 2026 homeowner purchase without qualified tax guidance.
Confirm the authority having jurisdiction, permit scope, installation location, clearances, access, and commissioning sequence. Before hurricane season—June 1 through November 30—have the installer demonstrate the backup functions included in the scope and document supported circuits, settings, and the outage plan. Keep an independent emergency plan for health or safety needs.