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Solar panels in Louisville, Kentucky: output, savings and payback

Solar panels in Louisville produce about 1,373 kWh a year for each kW installed, 9% less than the average of the 400 US cities in our data (1,517 kWh). Among the 2 Kentucky cities we cover, it ranks 1st of 2 for solar output, against an average there of 1,371 kWh.

Kentucky’s average residential electricity price for January to August 2026 was 14.20¢ per kWh, 3.99¢ below the US average of 18.19¢, according to the Energy Information Administration.

For a home using the US average of 899 kWh a month, a 7.9 kW system would cover a year’s use and save about $1,532 in its first year, or $52,225 over 25 years. With the average sunshine of the 400 US cities in our data, the same home would need a 7.1 kW system. Because Louisville gets less sun, it needs 10% more capacity to cover the same use, so at any price per watt the system costs 10% more and pays for itself later.

There is no verified US installed-price figure yet, so add the price per watt from your installer’s quote in the calculator below to see the payback period for Louisville.

A typical home in Louisville

System size
7.9 kW
Sized to cover 10,788 kWh a year
First-year generation
10,788 kWh
First-year savings
$1,532
At 14.20¢ per kWh
Savings over 25 years
$52,225
Prices rising 3% a year
Payback
Needs your quote
No verified US installed price yet: enter yours below

Assumes all the electricity the panels make is used at home, up to the home’s yearly use, and that panel output falls 0.5% a year. Power sent to the grid is counted at zero.

How Louisville compares

Louisville compared with the Kentucky and US averages
LouisvilleKentucky averageUS average
Solar output, kWh per kW a year1,3731,3711,517
Electricity price per kWh14.20¢14.20¢18.19¢
System size for a typical home7.9 kW7.9 kW7.1 kW
First-year savings$1,532$1,532$1,962

Averages are of the 2 places in Kentucky and the 400 US cities in our data, unweighted. The US column uses the US average price as well as the average sunshine.

Your home in Louisville

All amounts in US dollars.

Your home

Sets how much electricity each kW of panels makes in a year at your location.

kWh per month

Check your utility bill: most show monthly kWh. Average your last 12 months if you can.

cents per kWh

Starts at the Kentucky residential average for January to August 2026. Your bill shows your own rate.

Solar system
kW

Leave blank to size the panels to cover your yearly use, or enter the size on your quote.

Installed price
$per W

Enter the price from your installer quote to see cost, payback and return. Your quote divided by the system size in watts (for example, a 6 kW system is 6,000 W).

Assumptions you can change
% per year

Starts at 0.5%, the median of nearly 2,000 reported rates in an NREL review.

% per year

A scenario, not a forecast. Try 0% and 5% to see how much it matters.

%

Share of the panels’ output your home uses as it is made. 100% assumes all of it offsets power you would otherwise buy, up to your annual use.

A battery only adds savings when you use less than 100% of your solar power directly. Lower “Used directly at home” under assumptions to model that.

Results

Payback period

Add your installer’s quoted price to see payback

First-year savings
$1,532
Savings over 25 years
$52,225
System size
7.9 kW
Sized to cover your yearly use
First-year generation
10,788 kWh
Cumulative savings over 25 yearsAdd your quoted price to compare against the cost.
Year-by-year table
Generation and savings for each of the 25 years
YearGeneration (kWh)Price per kWhSaved that yearSaved so far
110,788$0.142$1,532$1,532
210,734$0.146$1,570$3,102
310,680$0.151$1,609$4,711
410,627$0.155$1,649$6,360
510,574$0.160$1,690$8,050
610,521$0.165$1,732$9,782
710,468$0.170$1,775$11,557
810,416$0.175$1,819$13,376
910,364$0.180$1,864$15,240
1010,312$0.185$1,911$17,151
1110,261$0.191$1,958$19,109
1210,209$0.197$2,007$21,115
1310,158$0.202$2,057$23,172
1410,107$0.209$2,108$25,280
1510,057$0.215$2,160$27,440
1610,007$0.221$2,214$29,654
179,957$0.228$2,269$31,922
189,907$0.235$2,325$34,248
199,857$0.242$2,383$36,631
209,808$0.249$2,442$39,073
219,759$0.256$2,503$41,576
229,710$0.264$2,565$44,141
239,662$0.272$2,629$46,769
249,613$0.280$2,694$49,464
259,565$0.289$2,761$52,225

Savings count only electricity your home no longer buys. Power sent to the grid is valued at zero. Grid emissions data has not been verified yet, so no carbon figure is shown. See the methodology for every formula and source.

Nearby cities

CityDistancekWh per kW a yearPrice per kWhSystem sizeFirst-year savings
Indianapolis, Indiana115 miles1,36417.04¢7.9 kW$1,838
Nashville, Tennessee151 miles1,36113.80¢7.9 kW$1,489
Columbus, Ohio190 miles1,32518.81¢8.1 kW$2,029
Chicago, Illinois276 miles1,36919.23¢7.9 kW$2,075
Atlanta, Georgia312 miles1,43515.48¢7.5 kW$1,670

Solar panels in Louisville: questions

How much electricity do solar panels produce in Louisville, Kentucky?
About 1,373 kWh a year for each kW of panels, for a roof-mounted, south-facing array at a 30° tilt with 14% system losses (PVWatts). A 7.9 kW system would make about 10,788 kWh in its first year. Shade, a different roof angle or an east or west-facing roof will change this.
How much could solar panels save in Louisville, Kentucky?
At Kentucky’s average residential price of 14.20¢ per kWh, a 7.9 kW system sized for an average US home would save about $1,532 in its first year and $52,225 over 25 years. That assumes the home uses all the power the panels make, electricity prices rise 3% a year and panel output falls 0.5% a year. Power sent to the grid is counted at zero. At the US average price of 18.19¢, the first-year figure would be $1,962.
How long do solar panels take to pay back in Louisville, Kentucky?
It depends on the installed price on your quote, which varies by installer and system, and we do not have a verified US average to use. Enter your quote in the calculator on this page: Louisville’s solar output and Kentucky’s electricity price are already filled in. Every $0.10 per watt adds about $790 to the price of a 7.9 kW system.
What do homes in Louisville, Kentucky pay for electricity?
Kentucky’s average residential price for January to August 2026 was 14.20¢ per kWh, against 18.19¢ for the US as a whole (EIA Electric Power Monthly, Table 5.6.B). Your own rate depends on your utility and plan, so use the figure from your bill in the calculator if you can.
How does Louisville compare with nearby cities?
Of the 5 nearest cities we cover, Atlanta (312 miles away) gets the most sun at 1,435 kWh per kW, and Columbus (190 miles away) the least at 1,325 kWh. Louisville gets 1,373 kWh. Within Kentucky, it ranks 1st of the 2 cities we cover.
Where do these figures come from?
Solar output is from the PVWatts V8 tool for Louisville’s coordinates in the Census Bureau Gazetteer, checked on 2026-11-11. The electricity price is the EIA residential average for Kentucky for January to August 2026, and household use is the EIA average for US homes. Each figure is listed with its source link at the bottom of this page.

Sources for this page

  • Solar output for Louisville: developer.nlr.gov (checked 2026-11-11)PVWatts V8.5.0 outputs.ac_annual for a 1 kW system. Weather data: 943735.csv, station at 38.16999816894531, -85.66000366210938 (1,212 m away).
  • Kentucky electricity price: www.eia.gov (checked 2026-11-11)Kentucky, residential sector, year-to-date through August 2026. Published as 14.20 cents per kilowatthour.
  • US average price: www.eia.gov (checked 2026-11-11)U.S. Total, residential sector, year-to-date through August 2026. Published as 18.19 cents per kilowatthour.
  • Typical household use: www.eia.gov (checked 2026-11-10)Average annual electricity sold to a U.S. residential utility customer in 2022: 10,791 kWh ("an average of about 899 kWh per month").
  • Panel output loss: docs.nlr.gov (checked 2026-11-10)Median of nearly 2,000 reported degradation rates: "a median value of 0.5%/year" (average 0.8%/year).
  • Location: www2.census.gov (checked 2026-11-10)Census Gazetteer INTPTLAT/INTPTLONG (internal point) for GEOID 2148006, "Louisville/Jefferson County metro government (balance)".

Methods and every other figure are on the methodology page.