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Off-grid solar in Florida

Florida off grid: size for December.

Near Jacksonville, 1 kW of panels makes about 3.00 kWh a day in December, 64% of what it makes in May. The essentials need about 920 W of panels and a 9.7 kWh battery.

Solar data updated · All states

Size an off-grid system in Florida

2. What you run each day
  • Refrigerator2.3 kWh
  • Chest or upright freezer—
  • LED light bulb (9 W)180 Wh
  • Phone charge (15 Wh each)30 Wh
  • Wi-Fi router (10 W)240 Wh
  • CPAP with heated humidifier (28 W)—
  • Laptop (60 W)—
  • TV (typical main TV)—
  • Microwave—
  • Well pump (1/3 HP, 1,000 W)—
  • Furnace blower fan (1/3 HP, 700 W)—
  • 12 V compressor cooler—

Hours are example settings. Change them to how you live. Watts × hours a day = watt-hours (Wh) a day.

3. Days the battery must last with little sun
4. Battery type

Your use

2.7 kWh a day

Solar panels

920 W

About 3 × 400 W panels. In December, 1 kW of panels in Jacksonville makes about 3.00 kWh a day.

Battery bank

9.7 kWh

2.7 kWh × 3 days ÷ 85% usable.

Sized for December, the darkest month. The rest of the year you will have spare power. The US Department of Energy also advises a backup generator for long cloudy spells.

Kits you can buy for this in Florida

Complete kits from each brand's own store: the power station, batteries and that brand's own panels. One button puts every item in the brand's cart; you review and check out on their site. Prices checked Oct 26, 2026 and they change.

Disclosure: We may earn a commission if you buy through these links. It never changes our recommendations. How we make money.

Solar output through the year near Jacksonville

kWh per month from 1 kW of panels near Jacksonville, Florida
kWh per month from 1 kW of panels near Jacksonville, Florida
Jan103 kWh
Feb105 kWh
Mar133 kWh
Apr139 kWh
May145 kWh
Jun126 kWh
Jul132 kWh
Aug128 kWh
Sep116 kWh
Oct121 kWh
Nov99 kWh
Dec93 kWh

December gives 93 kWh per kW for the month; May gives 145. A system sized for May would fall short every winter.

Cabin and home sizes in Florida

Off-grid solar and battery size in Florida for three example cabins and homes
UseA dayPanelsBattery (3 days)
Weekend cabinLights, phones and a 12 V compressor cooler instead of a fridge492 Wh160 W1.7 kWh
Part-time cabinA full-size fridge, Wi-Fi, lights, a laptop and a TV3.7 kWh1,220 W13 kWh
Full-time homeFridge, freezer, well pump, furnace blower, microwave and the rest11 kWh3,610 W38 kWh

See which kits fit each size, or what going off grid costs.

These sizes assume panels at a 20 degree tilt. A steeper tilt, which also sheds snow, catches more low winter sun, and many off-grid homes in the far north run a generator for the darkest weeks rather than buying panels for December alone.

For vans and RVs, see Camper Volts.

Similar winter sun

Frequently asked questions

How much solar do I need to live off grid in Florida?

Size for December. Near Jacksonville, 1 kW of panels makes about 3.00 kWh a day in December in the PVWatts model. A fridge, Wi-Fi, four LED bulbs and two phone charges (2.7 kWh a day) need about 920 W of panels and a 9.7 kWh lithium battery for 3 days with little sun. A full-time home with a freezer, well pump and furnace blower needs about 3,610 W and 38 kWh.

Is Florida good for off-grid solar in winter?

Florida ranks 8th of 51 states and DC for December solar output in our model, 36% more than the middle state. December output is 64% of May, the best month here, so a system sized for winter has plenty of spare power in summer.

How big a battery bank do I need off grid in Florida?

Battery size depends on use, not on sun: daily watt-hours × days of storage ÷ the usable share (85% for lithium). For 2.7 kWh a day and 3 days, that is 9.7 kWh. The US Department of Energy advises sizing for cloudy stretches and keeping a backup generator.

Why does winter matter so much for off-grid solar in Florida?

Short days and low sun. To cover the same 2.7 kWh a day, panels near Jacksonville would need only about 590 W in May but 920 W in December. Off grid, there is no utility to cover the gap, so the winter number is the one to buy.

Estimates only. Output is modeled near Jacksonville; mountains, coast, shade and snow change it. Size a real system with an installer or an off-grid supplier before you buy. See our disclaimer.

Sources

  1. PVWatts v8 solar model (National Laboratory of the Rockies, formerly NREL, run via its PySAM package) on NASA POWER hourly weather — monthly output per kW by state, average of 2015-2024 hourly weather; 1 kW DC fixed roof mount, 20 degree tilt, facing south (180 degrees), standard module, 14% system losses, 96% inverter efficiency, DC/AC ratio 1.2 (PVWatts defaults except tilt). Checked against the PVWatts web API for eight states: within 8%, 3% on average.
  2. PVWatts v8 API documentation (National Laboratory of the Rockies) — monthly AC output; 14% system losses
  3. US DOE Energy Saver, Estimating appliance and home electronic energy use (archived copy) — watts × hours a day ÷ 1,000 = kWh a day
  4. US DOE Energy Saver, Balance-of-system equipment for renewable energy systems (archived copy) — balance-of-system equipment (batteries, controllers, inverters, wiring) could be half of a stand-alone system's cost; size batteries for cloudy weather, with a backup generator
  5. EIA Residential Energy Consumption Survey 2020, table CE4.6.EL.ST — refrigerators: 839 kWh a year per household
  6. EIA Residential Energy Consumption Survey 2020, table CE5.3b (detailed electricity end use) — separate freezers 570 kWh, most-used TV 210 kWh, microwaves 107 kWh a year per household
  7. Eugene Water & Electric Board, Generator sizing considerations — running and starting watts: well pump 1/3 HP 1,000 W (+2,000 W to start), furnace fan blower 1/3 HP 700 W (+1,400), refrigerator/freezer 700 W (+2,200), microwave 1,000 W, laptop 60 W, phone charger 20 W
  8. US DOE Energy Saver, Energy efficient lighting fact sheet (2021) — a 1,100-lumen LED screw-in bulb uses as little as 9 W
  9. EnergySage, How many watts does a Wi-Fi router use? — 5 to 20 W; we use 10 W
  10. TidBITS, iPhone battery-life tables — iPhone 16 battery 13.84 Wh; we use 15 Wh a charge to allow for charging losses
  11. ResMed battery guide (AirSense 10) — 28 W with heated humidifier, about 11 W without
  12. Dometic CFX3 35 specifications — 0.98 Ah an hour at 12 V on a 90°F day
  13. Renogy Deep Cycle AGM Battery 12V 100Ah product page — rated at 50% depth of discharge

Photo: Watt A Lot on Unsplash (Unsplash License).