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Solar panels in Louisville, Kentucky
Louisville receives 4.17 peak sun hours a day and 1,523 kWh/m² of solar energy a year. That is measured satellite data for Louisville's coordinates, not a national average — and it changes the panel count.
Louisville solar data
4.17peak sun hours/day
1,523annual irradiance (kWh/m²)
1.38kWh/day from one 400 W panel
503kWh/year from one 400 W panel
Monthly solar irradiance in Louisville
| Month | Peak sun hours/day | Share of year |
|---|---|---|
| January | 1.64 | 0.1 |
| February | 3.30 | 0.3 |
| March | 3.92 | 0.3 |
| April | 4.98 | 0.4 |
| May | 5.54 | 0.5 |
| June | 6.34 | 0.5 |
| July | 5.91 | 0.5 |
| August | 5.97 | 0.5 |
| September | 4.45 | 0.4 |
| October | 4.08 | 0.3 |
| November | 2.07 | 0.2 |
| December | 1.73 | 0.1 |
Source: NASA POWER daily point API, parameter ALLSKY_SFC_SW_DWN (global horizontal irradiance), year 2024. Coordinates 38.2527, -85.7585.
How many solar panels does Louisville need?
For a typical US household using 900 kWh a month, Louisville needs about 22 panels of 400 W (8.71 kWp), with a south-facing roof. That is more panels than the same household would need in a city with 4.5 peak sun hours.