Peak sun hours in Alabama
Alabama averages 4.6 peak sun hours a day across the year, 20th of the 50 states. At that figure a 400-watt panel produces about 1.42 kWh a day after real-world losses, and covering the 900 kWh average US bill takes about 21 panels. Birmingham, the state's biggest city, sits at 4.6 hours, close enough to the statewide figure to use either, though elevation and distance from water still move the number street by street.
solid mid-pack sun: 4.6 of a possible ~6.5 hours
Panel counts for Alabama bills
Computed at Alabama's 4.6 hours with 400W panels and the 0.77 derate; the US-average column shows what the same bill takes at 4.5 hours, so you can see what your state's sun is worth in hardware.
| Monthly usage | Alabama | System size | US average |
|---|---|---|---|
| 500 kWh/mo | 12 panels | 4.8 kW | 12 panels |
| 750 kWh/mo | 18 panels | 7.2 kW | 18 panels |
| 900 kWh/mo | 21 panels | 8.4 kW | 22 panels |
| 1,000 kWh/mo | 24 panels | 9.6 kW | 24 panels |
| 1,500 kWh/mo | 35 panels | 14 kW | 36 panels |
| 2,000 kWh/mo | 47 panels | 18.8 kW | 48 panels |
What 4.6 hours means in practice
Alabama is mid-pack American sun: 20th of 50 at 4.6 peak sun hours, within 2% of the national average. The 900 kWh average bill lands at 21 panels against 22 nationally. At this tier the resource neither makes nor breaks the project, which is what the rate and the seasonal spread below are for.
How a Alabama year is shaped
The 4.6-hour figure is an annual average, and no month is average. These are the twelve monthly means for Alabama from NASA's 2001-2020 solar climatology, each as a share of the state's own annual mean, with that share applied to the 4.6-hour planning figure. June and December are marked.
| Month | Share of the annual average | Peak sun hours (est.) |
|---|---|---|
| January | 60% | 2.8 |
| February | 72% | 3.3 |
| March | 97% | 4.5 |
| April | 124% | 5.7 |
| May | 136% | 6.2 |
| June | 137% | 6.3 |
| July | 132% | 6.1 |
| August | 122% | 5.6 |
| September | 109% | 5.0 |
| October | 89% | 4.1 |
| November | 69% | 3.2 |
| December | 53% | 2.4 |
Alabama has a shallow year by American standards, 2.6 to one between June and December, which still returns 53% of the annual average, around 2.4 hours a day. Only 44% of the light lands in the four best months, against 6.3 hours at the June peak. Nothing here is seasonal enough to change how you size a grid-tied array.
Half the Alabama calendar sits above the annual average and half below: April through September are the six months that beat it, carrying 63% of the year's light. April is already worth about 5.7 hours a day, so the productive half of the year starts earlier than most people expect.
That matters most where homes are hungry, and Alabama's are: EIA put the average household here at 1,143 kWh a month in 2024, 32% above the national 863. Covering that bill on an annual average takes 27 panels. Covering it inside a Alabama December, with no grid and no bank of summer credit, takes 51, about 1.9 times as many. Grid-tied you never see the difference. Off-grid it is the whole design.
Alabama is more uniform than most. The 11 grid cells sampled across the state span 7%, sunniest in the southeast and dimmest in the north, which scales to about 4.8 hours against 4.4. Enough to notice on a production estimate, not enough to change which system you buy. Birmingham sits inside that band, not at the edge of it.
What that sun is worth on a Alabama bill
| EIA, 2024 residential averages | Alabama | United States |
|---|---|---|
| Average home's monthly use | 1,143 kWh | 863 kWh |
| Price per kilowatt-hour | 15.18¢ | 16.48¢ |
| Average monthly bill | $173.50 | $142.26 |
| One 400W panel, a year's output | 517 kWh | 506 kWh |
| What that output displaces | $79 | $83 |
At 15.18¢ a kilowatt-hour Alabama sits 8% below the national 16.48¢, 20th of the fifty states on price. One 400-watt panel offsets roughly $79 of Alabama power a year. Mid-table on rates means the project lives or dies on the quote and the net-metering terms rather than on either the sun or the tariff.
Alabama lands in much the same place on both rankings, 20th for sun and 21st for what a panel earns, so its position in the sun table is a fair guide to its position on value. That is not automatic. Idaho gets the same sun (4.6 hours to Alabama's 4.6) and pays 11.52¢ against 15.18¢, so one panel is worth about $19 more a year in Alabama than in Idaho.
Two warnings on those dollar figures. They are displaced electricity and nothing else: no install cost, no incentive, no financing, and no assumption about how your utility settles a surplus, which is the single biggest unknown in the sum. And a state average hides the utility you are actually on; 15.18¢ is every Alabama residential customer averaged together, and neighbouring territories can differ by more than the gap between two states in the ranking.
Getting a number for your address
For a location-exact figure, run your address through NREL's free PVWatts; it uses measured weather for your grid cell and will also model roof tilt and direction, which statewide numbers cannot. Then compare its annual kWh against a quote's promise before you sign anything.
Questions people ask
How many solar panels do I need in Alabama?
About 21 400-watt panels (8.4 kW) for the 900 kWh a month an average US home uses, at Alabama's 4.6 peak sun hours. For the average Alabama home specifically, which EIA measured at 1,143 kWh a month in 2024, it is 27. Your own bill is the variable that matters, and the calculator takes any figure.
Is 4.6 peak sun hours good for solar?
It is solidly workable. Alabama sits near the national average of 4.5 hours, so panel counts here match the US-typical figures, and project economics turn on your utility's rates and net-metering terms rather than on the sun.
How much is one solar panel worth a year in Alabama?
About $79. One 400-watt panel at Alabama's 4.6 peak sun hours makes roughly 517 kWh a year after the 0.77 derate, and Alabama residential electricity averaged 15.18¢ a kilowatt-hour in 2024 (EIA), which puts Alabama 21st of the 50 states on this measure against 20th on sunlight alone. That figure is displaced electricity only. It says nothing about install cost, incentives, or how your utility settles a surplus.
Do peak sun hours change with the seasons in Alabama?
Yes, by a factor of 2.6 here. NASA's 2001-2020 climatology puts Alabama's June at 137% of the annual average and December at 53%, so the 4.6-hour figure on this page is the midpoint of a curve running from roughly 6.3 hours a day down to 2.4. Grid-tied homes bank the summer surplus as credit; off-grid designs have to size for the trough, and in Alabama that means 51 panels for an average local bill instead of 27.