Solar panels in Louisville, KY
Roofs in Louisville get about 1,413 hours of usable sunlight a year — less than 67% of the cities we've measured. Here's what that means in cost, savings and payback, using real rooftop data rather than a national average.
Check your specific roof in Louisville → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Louisville solar system costs
A 23-panel system (9.2 kW) is about right for an average Louisville home using 10,800 kWh a year. It would produce roughly 11,050 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 3,843 | $6,384 | $469 | 13.6 yrs |
| 12 panels | 4.8 kW | 5,765 | $9,576 | $703 | 13.6 yrs |
| 16 panels | 6.4 kW | 7,687 | $12,768 | $938 | 13.6 yrs |
| 20 panels | 8 kW | 9,608 | $15,960 | $1,172 | 13.6 yrs |
| 26 panels | 10.4 kW | 12,491 | $20,748 | $1,369 | 15.2 yrs |
How we worked this out for Louisville
Every number on this page comes from these seven steps. Nothing is a national average — the sunlight figure is measured from Louisville rooftops.
| # | Step | Result |
|---|---|---|
| 1 | What one panel makes here 400W ÷ 1000 × 1,413 sun hrs × 0.85 system losses |
480 kWh/yr |
| 2 | Panels needed to cover typical usage 10,800 kWh ÷ 480 kWh per panel |
23 panels |
| 3 | System size 23 panels × 400W |
9.20 kW |
| 4 | Annual production 9.20 kW × 1,413 hrs × 0.85 |
11,050 kWh/yr |
| 5 | Installed cost 9,200 W × $2.85 per watt, then −30% federal credit |
$18,354 |
| 6 | Annual saving 3,780 kWh used as generated × 12.2¢ + 7,270 kWh exported × 12.2¢ |
$1,325/yr |
| 7 | Payback $18,354 ÷ $1,325 per year |
13.8 years |
Step 6 matters more than it looks. Only 34% of what a system this size produces in Louisville is used the moment it is generated; the other 7,270 kWh is exported and credited one-for-one under net metering. Because exports here are credited at or near retail, that split changes the payback very little — 13.6 years against the 13.8 we show. In places where exports pay a fraction of retail the same split moves payback by years, which is why we model it explicitly rather than assuming.
Assumptions: 400W panels, 15% system losses (inverter, wiring, heat, soiling), $2.85/W installed, 10,800 kWh typical annual household use, 12.2¢/kWh electricity. Change any of those and every figure above moves — which is exactly why a single national "solar costs X" number is misleading.
Notice that payback barely improves as systems get bigger, and eventually gets worse. That's because you can only save money on electricity you were going to buy anyway. Once a system covers your usage, extra panels mostly generate exports at a much lower rate.
Why Louisville gets 1,413 sun hours
That figure comes from Google's analysis of real rooftops across Louisville — it already accounts for shading from trees, chimneys and neighbouring buildings, which is why it's lower than the raw "hours of daylight" figures you'll see elsewhere. An unusually open, unshaded roof in Louisville reaches about 1,577 hours, roughly 12% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,413 hrs/yr |
|---|---|
| Unshaded roof | 1,577 hrs/yr |
| Electricity rate (Kentucky avg) | 12.2¢/kWh |
| Installed cost assumed | $2.85/W |
| Panel size assumed | 400 W |
| Federal tax credit | 30% |
| Typical household usage | 10,800 kWh/yr |
| Power used as generated | 34% |
| Paid for exported power | full retail (net metering) |
| Rooftops sampled here | 7 |
| Google imagery from | 2023 |
When Louisville actually produces
Annual totals hide the thing that catches people out: 35% of Louisville's yearly sunlight arrives in May–July, and just 14% across November–January.
| Month | Sun hrs | Share of year |
|---|---|---|
| Jan | 66 | |
| Feb | 88 | |
| Mar | 115 | |
| Apr | 143 | |
| May | 162 | |
| Jun | 170 | |
| Jul | 166 | |
| Aug | 150 | |
| Sep | 125 | |
| Oct | 96 | |
| Nov | 71 | |
| Dec | 60 |
Louisville produces about 2.8× as much in Jun as in Dec — a normal mid-latitude swing. Expect real winter shortfall and summer surplus rather than steady year-round output.
The annual total is measured from Google's rooftop imagery. Its split across months is calculated from solar geometry at Louisville's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.
How Louisville compares to the other 788 cities
| Measure | Louisville | Rank of 788 |
|---|---|---|
| Usable sunlight | 1,413 hrs | 523rd |
| Sunlight lost to shade | 10% | 62nd most |
| Median roof size | 196 m² | 382nd largest |
| Electricity rate | 12.2¢ | 670th highest |
| Payback | 13.8 yrs | 685th fastest |
| Grid carbon | 802 kg/MWh | 136th dirtiest |
What actually stands out about Louisville:
- Shading is a real problem here. Louisville loses 10% of its potential sunlight to trees, chimneys and neighbouring buildings — the 62nd-worst of the 788 cities measured. Panel placement matters more here than in most places, and a roof survey is worth more than a phone quote.
- Dimmer than the rest of Kentucky. Louisville roofs get 8% less usable sunlight than the typical Kentucky city we've measured — statewide averages will overstate what you can expect here.
Cities with almost the same sunlight
These are the closest matches to Louisville's 1,413 usable sun hours from other states and provinces. Same sunlight, different electricity prices — which is usually what decides whether solar is worth it.
| City | Sun hrs | Rate | Payback |
|---|---|---|---|
| Jamestown, NY | 1,413 | 24.3¢ | 7 yrs |
| Columbus, OH | 1,414 | 15.2¢ | 11.1 yrs |
| Schenectady, NY | 1,414 | 24.3¢ | 7 yrs |
| Jackson, TN | 1,414 | 12.1¢ | 14 yrs |
Nearby cities
See all of Kentucky → statewide sunlight, rates, incentives and every city we've measured.
Louisville solar questions
How many solar panels do I need in Louisville?
About 23 panels for an average home using 10,800 kWh a year. Louisville roofs get 1,413 usable sun hours, so each 400W panel produces roughly 480 kWh annually. A typical Louisville roof fits about 60 panels, so roof space is unlikely to be your limit.
Is solar worth it in Louisville?
At 12.2¢/kWh and 1,413 sun hours, a typical system pays for itself in about 13.8 years and returns roughly $14,776 over a 25-year panel life. That is slower than average, so compare several quotes before committing. Exported power earns full retail credit here.
How much do solar panels cost in Louisville?
A 9.2 kW system costs about $26,220 before incentives and $18,354 after the 30% federal tax credit. That works out near $2.85 per watt installed. Roof pitch, shading, electrical panel upgrades and equipment choice move the price most, which is why quotes for the same house can differ by thousands.
Worth reading before you buy
Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average Kentucky electricity rates. Not a quote and not financial advice. Your roof, usage, utility plan and local incentives will change these numbers — get real quotes before buying.