How Big a Home Battery Do You Need for a Hurricane Outage?

The right home battery size for a hurricane outage depends on two numbers: how much power your must-run appliances draw at the same moment (kilowatts) and how much energy they use over a day (kilowatt-hours). Most Panhandle homeowners size a battery to keep essentials running, not the whole house, and pair it with solar so it can recharge each day while the grid is down.

Two numbers that decide battery size: kW and kWh

Battery specifications list two ratings, and both matter during a storm outage.

• Power (kW) is how much the battery can deliver at one moment. It decides whether your air conditioner, well pump and refrigerator can all run at once, and whether a large motor can start without tripping the battery.
• Energy (kWh) is how much the battery stores. It decides how many hours those loads can run before the battery is empty.

A battery with plenty of storage but too little power output will shut off when a big load kicks on. A battery with strong output but little storage will run everything for a short time and then go dark. Good sizing balances both against what your home actually needs.

For reference, a single Tesla Powerwall 3 stores 13.5 kWh of usable energy and can deliver up to 11.5 kW continuously. Additional expansion units add storage. Other brands publish similar ratings on their spec sheets, and those two lines are the ones to compare.

Step 1: List the loads you cannot go without

Start with a short list, not the whole house. After a hurricane in the Panhandle, the usual priorities are:

• Refrigerator and freezer, so food and medication stay cold
• Well pump, if your home is on a private well
• Lights, phone and laptop charging, internet router and a TV or radio for news
• Ceiling fans, and possibly one window unit or a mini-split for a bedroom
• Medical equipment such as CPAP machines or oxygen concentrators
• A garage door opener and a sump or lift pump if you have one

Central air conditioning, electric water heaters, electric ranges, dryers and pool pumps are the large loads. They can run on battery, but each one you add raises the size and cost quickly. Deciding early whether central AC is on the list is the single biggest choice in battery sizing.

Step 2: Estimate peak power and daily energy

Look at the nameplate label on each appliance, or the owner's manual, for its watts or amps. Multiply amps by volts (120 or 240) to get watts. Then estimate how many hours a day each item actually runs. A refrigerator compressor cycles on and off, so it does not run 24 hours straight; a fan or router runs nearly all day.

Add up two totals:

1. Peak power: the largest combination of loads likely to run at the same time, plus extra for motor starts. Well pumps and AC compressors draw several times their running power for a moment when they start.
2. Daily energy: watts multiplied by hours of use for each item, added together and divided by 1,000 to get kWh per day.

Your utility bill also helps. FPL, CHELCO, Gulf Coast Electric, West Florida Electric, Escambia River Electric and Talquin all show monthly kWh use. Dividing a mild-weather month by 30 gives a rough whole-home daily figure; your essentials-only figure should be well below that.

Step 3: Decide how many days you need to cover

After Hurricanes Michael and Sally, parts of the Panhandle were without grid power for many days, and rural co-op lines often take longer to restore than town circuits. When you size a battery, think in days, not hours.

This is where solar changes the math. A battery on its own is a fixed tank: once it is empty, it stays empty until the grid returns. A battery paired with solar panels refills during the day, so it only needs to carry you through the evening and overnight. With solar, sizing becomes a question of whether daytime production can replace what you use overnight, rather than whether one charge can last the whole outage.

Cloudy days after a storm reduce production, so plan for a margin. Many homeowners size storage to cover one night of essentials comfortably and accept trimming use if a cloudy day follows.

A worked example (illustrative numbers)

Suppose a household decides its essentials are a refrigerator, a chest freezer, a well pump, lights, fans, a router, phone charging and one ductless mini-split for a bedroom at night. After checking labels and estimating run times, they arrive at roughly 12 kWh per day, with a peak of about 6 kW when the well pump starts while the mini-split is running.

• Battery only: one 13.5 kWh battery covers about one day of those loads. A three-day outage would need roughly three times the storage, or strict rationing.
• Battery plus solar: if the solar array produces more than 12 kWh on a typical sunny day, one battery can be recharged each day and carry the overnight portion, covering a longer outage as long as the weather cooperates.
• Adding central AC: a central system can draw several kilowatts while running for many hours on a hot September day. Adding it could double or triple daily energy needs and usually calls for more than one battery and a larger solar array.

These numbers are only an example. Your appliances, insulation and habits will give a different answer, which is why an on-site look at your panel and loads matters.

Whole-home backup vs essential-loads backup

There are two common ways to wire a battery:

• Essential-loads panel: selected circuits are moved to a separate subpanel that the battery powers during an outage. Everything else stays dark. This keeps the battery from being drained by loads you did not plan for.
• Whole-home backup: the battery backs up the main panel, so every circuit has power. This is more convenient, but you must manage use yourself, because the battery cannot tell a pool pump from a refrigerator. Some systems add load controllers to shed large appliances automatically.

Whole-home backup with careful habits works well for many households. Essential-loads backup is simpler for anyone who would rather not think about it in the middle of a storm.

Battery vs generator for long Panhandle outages

A standby generator runs as long as fuel lasts, which is its main advantage in a long outage. It also needs fuel delivery or a large propane tank, regular exercise and maintenance, and it makes noise and exhaust. A battery is silent, needs no fuel and switches over automatically, but it only lasts as long as its stored energy unless solar refills it.

Some homes use both: solar and a battery for everyday savings and short outages, with a generator kept for an extended event. If you already own a generator, ask whether it can be integrated safely with your battery system rather than replaced.

Adding a battery to an existing solar system

Many Panhandle homes already have rooftop solar that shuts off during a grid outage. Grid-tied inverters are required to stop exporting when the grid goes down so line workers are not put at risk. Adding a battery and the right controls lets that existing array keep producing while you are islanded from the grid.

Compatibility depends on your inverter brand, age and wiring. MSM Solar works on systems of any brand and age, including systems whose original installer has closed, and can look at whether a battery can be added to what you have. See our solar system additions page for how expansions work, or our new installations page if you are starting from scratch.

What a home battery costs and what changed in 2026

For budgeting, MSM Solar's typical price for a first Tesla Powerwall 3 is about $15,000 installed. Additional storage, an essential-loads subpanel or electrical upgrades change the total, and a free site survey gives you a written quote for your home.

The federal residential tax credit for home batteries ended along with the residential solar credit for systems installed after December 31, 2025, so homeowners should not count on a federal credit for a new battery. Businesses may still qualify for a federal clean-energy credit on systems placed in service by the end of 2027; ask a tax advisor. Florida has no state solar or battery tax credit, but solar equipment is exempt from state sales tax.

Frequently asked questions

Can one battery run my central air conditioner?

Sometimes, for a limited time. Whether it works depends on the AC unit's starting and running power compared with the battery's output rating, and on how long you need it to run. Many homeowners run a smaller mini-split or window unit on battery instead to stretch stored energy.

Will my solar panels charge the battery during an outage?

Yes, if the system is designed for backup. With a battery and the correct controls, the solar array keeps producing while the home is disconnected from the grid and charges the battery during daylight.

How many batteries do I need for my whole house?

It depends on your daily kWh use, your peak loads and whether you have solar to recharge. Homes that want to run central AC, an electric water heater and a pool pump through a multi-day outage typically need more than one battery. A site survey that reviews your bills and electrical panel gives a specific answer.

Should I charge my battery to 100% before a hurricane?

Yes. Most battery apps have a storm or backup-reserve setting that keeps the battery full ahead of severe weather. Check that it is turned on at the start of hurricane season.

Conclusion

MSM Solar works with homeowners in Perdido Key, Ponce de Leon, Alford, Altha and Cantonment, and in every town between Pensacola and Apalachicola.

Sizing a home battery for a hurricane outage comes down to listing your true essentials, adding up their peak power and daily energy, and deciding how many days you need to cover. Pairing the battery with solar lets it refill each day, which matters most in the long outages the Panhandle sees after major storms. Whether you live in Crestview, Niceville or Panama City, MSM Solar, Florida Certified Solar Contractor CVC57236, offers free site surveys and written quotes. Call (850) 737-5197 and a real person will get back to you within two business days.