Peak sun hours in Tennessee
Tennessee averages 4.4 peak sun hours a day across the year, 25th of the 50 states. At that figure a 400-watt panel produces about 1.36 kWh a day after real-world losses, and covering the 900 kWh average US bill takes about 22 panels. Nashville, the state's biggest city, runs slightly ahead of the statewide figure at 4.5 hours; treat 4.4 as the midpoint of a real spread rather than a local reading.
solid mid-pack sun: 4.4 of a possible ~6.5 hours
Panel counts for Tennessee bills
Computed at Tennessee's 4.4 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 | Tennessee | System size | US average |
|---|---|---|---|
| 500 kWh/mo | 13 panels | 5.2 kW | 12 panels |
| 750 kWh/mo | 19 panels | 7.6 kW | 18 panels |
| 900 kWh/mo | 22 panels | 8.8 kW | 22 panels |
| 1,000 kWh/mo | 25 panels | 10 kW | 24 panels |
| 1,500 kWh/mo | 37 panels | 14.8 kW | 36 panels |
| 2,000 kWh/mo | 49 panels | 19.6 kW | 48 panels |
What 4.4 hours means in practice
Tennessee is mid-pack American sun: 25th of 50 at 4.4 peak sun hours, within 2% of the national average. The 900 kWh average bill lands at 22 panels, same as the US-average count. 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 Tennessee year is shaped
The 4.4-hour figure is an annual average, and no month is average. These are the twelve monthly means for Tennessee from NASA's 2001-2020 solar climatology, each as a share of the state's own annual mean, with that share applied to the 4.4-hour planning figure. June and December are marked.
| Month | Share of the annual average | Peak sun hours (est.) |
|---|---|---|
| January | 53% | 2.3 |
| February | 66% | 2.9 |
| March | 93% | 4.1 |
| April | 123% | 5.4 |
| May | 136% | 6.0 |
| June | 149% | 6.5 |
| July | 142% | 6.2 |
| August | 131% | 5.7 |
| September | 112% | 4.9 |
| October | 86% | 3.8 |
| November | 63% | 2.8 |
| December | 47% | 2.0 |
The gap between Tennessee's best month and its worst is 3.2 to one: June at 149% of the annual average, December at 47%, or about 6.5 hours a day against 2.0. Four months carry 46% of the year's light. A grid-tied system rides that out on net metering without anyone noticing.
Half the Tennessee calendar sits above the annual average and half below: April through September are the six months that beat it, carrying 66% of the year's light. April is already worth about 5.4 hours a day, so the productive half of the year starts earlier than most people expect.
That matters most where homes are hungry, and Tennessee's are: EIA put the average household here at 1,154 kWh a month in 2024, 34% above the national 863. Covering that bill on an annual average takes 29 panels. Covering it inside a Tennessee December, with no grid and no bank of summer credit, takes 61, about 2.1 times as many. Grid-tied you never see the difference. Off-grid it is the whole design.
Tennessee is more uniform than most. The 13 grid cells sampled across the state span 6%, sunniest in the southwest and dimmest in the northeast, which scales to about 4.5 hours against 4.3. Enough to notice on a production estimate, not enough to change which system you buy. Nashville sits inside that band, not at the edge of it.
What that sun is worth on a Tennessee bill
| EIA, 2024 residential averages | Tennessee | United States |
|---|---|---|
| Average home's monthly use | 1,154 kWh | 863 kWh |
| Price per kilowatt-hour | 12.42¢ | 16.48¢ |
| Average monthly bill | $143.32 | $142.26 |
| One 400W panel, a year's output | 495 kWh | 506 kWh |
| What that output displaces | $61 | $83 |
Cheap power cuts the other way. Tennessee residential electricity averaged 12.42¢ a kilowatt-hour in 2024, 25% under the national 16.48¢ and 9th cheapest in the country, so the same panel that offsets $83 a year at national rates offsets about $61 here. Nothing is wrong with the sun. There is just less money in each kilowatt-hour it makes.
Here the sun ranking flatters Tennessee. 25th of fifty for sunlight, but only 46th for what a panel earns in a year, a drop of 21 places, and the reason is entirely the price of the electricity being replaced. Alabama gets more sun (4.6 hours to Tennessee's 4.4) and pays 15.18¢ against 12.42¢, so one panel is worth about $17 less a year in Tennessee than in Alabama.
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; 12.42¢ is every Tennessee 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 Tennessee?
About 22 400-watt panels (8.8 kW) for the 900 kWh a month an average US home uses, at Tennessee's 4.4 peak sun hours. For the average Tennessee home specifically, which EIA measured at 1,154 kWh a month in 2024, it is 29. Your own bill is the variable that matters, and the calculator takes any figure.
Is 4.4 peak sun hours good for solar?
It is solidly workable. Tennessee 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 Tennessee?
About $61. One 400-watt panel at Tennessee's 4.4 peak sun hours makes roughly 495 kWh a year after the 0.77 derate, and Tennessee residential electricity averaged 12.42¢ a kilowatt-hour in 2024 (EIA), which puts Tennessee 46th of the 50 states on this measure against 25th 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 Tennessee?
Yes, by a factor of 3.2 here. NASA's 2001-2020 climatology puts Tennessee's June at 149% of the annual average and December at 47%, so the 4.4-hour figure on this page is the midpoint of a curve running from roughly 6.5 hours a day down to 2.0. Grid-tied homes bank the summer surplus as credit; off-grid designs have to size for the trough, and in Tennessee that means 61 panels for an average local bill instead of 29.