Solar Panel Calculator for Madison, WI
Estimate the cost, savings and payback of solar panels in Madison, WI, using local NREL sunshine data, Wisconsin prices and electricity rates.
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Madison gets about 4.53 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,314 kWh a year. That ranks #89 of the 111 cities on this site. Output peaks in Jul and is lowest in Dec.
Sunshine in Madison by month
What an 8 kW system makes in Madison
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 2.62 | 576 kWh | $110 |
| Feb | 3.90 | 752 kWh | $143 |
| Mar | 4.75 | 968 kWh | $184 |
| Apr | 5.23 | 1,008 kWh | $192 |
| May | 5.89 | 1,136 kWh | $216 |
| Jun | 6.25 | 1,136 kWh | $216 |
| Jul | 6.32 | 1,160 kWh | $221 |
| Aug | 5.80 | 1,080 kWh | $206 |
| Sep | 5.12 | 952 kWh | $181 |
| Oct | 3.47 | 696 kWh | $133 |
| Nov | 2.85 | 576 kWh | $110 |
| Dec | 2.15 | 472 kWh | $90 |
| Year | 4.53 | 10,512 kWh | $2,003 |
Savings at 19.05¢ per kWh (Wisconsin average), with every kWh credited at that price.
Cost and payback by system size
At $3.03 per watt, the Wisconsin average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $12,120 | $1,001 | 12.5 yrs | $11,466 |
| 6 kW | $18,180 | $1,502 | 12.5 yrs | $17,199 |
| 8 kW | $24,240 | $2,003 | 12.5 yrs | $22,932 |
| 10 kW | $30,300 | $2,503 | 12.5 yrs | $28,665 |
| 12 kW | $36,360 | $3,004 | 12.5 yrs | $34,397 |
How many panels you need in Madison
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 4.57 kW | 12 |
| 750 kWh | 6.85 kW | 18 |
| 1,000 kWh | 9.13 kW | 23 |
| 1,500 kWh | 13.70 kW | 35 |
| 2,000 kWh | 18.26 kW | 46 |
Covering 100% of a year's use at 1,314 kWh per kW.
Common questions
Is solar worth it in Madison?
At local averages an 8 kW system costs about $24,240 before incentives, saves about $2,003 in its first year and pays back in about 12.5 years.
How many peak sun hours does Madison get?
About 4.53 a day over the year on a south-facing roof at 20°, from 2.1 in Dec to 6.3 in Jul, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in Madison?
About 1,314 kWh a year, or 110 kWh a month on average.
Is there a federal solar tax credit?
Not for homeowners who buy their system. The 30% Residential Clean Energy Credit ended for systems installed after December 31, 2025.
Sources
- NREL PVWatts V8 API (south-facing, 20° tilt, 14% losses, typical-year weather): https://developer.nlr.gov/docs/solar/pvwatts/v8/
- EnergySage, Solar panel cost by state (updated November 6, 2026): https://www.energysage.com/local-data/solar-panel-cost/
- U.S. EIA, Electric Power Monthly, Table 5.6.B (residential price, Jan–Aug 2026): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_b