State
How much solar do I need in Illinois?
Illinois averages 4.51 peak sun hours a day, so 1 kW of panels makes about 1,308 kWh a year. A home using 10 kWh a day needs about 2,956 W of panels.
| Daily use | Panel watts | 400 W panels | Battery for 1 day |
|---|---|---|---|
| 5 kWh/day | 1,478 W | 4 | 6.17 kWh |
| 10 kWh/day | 2,956 W | 8 | 12.35 kWh |
| 20 kWh/day | 5,913 W | 15 | 24.69 kWh |
| 30 kWh/day | 8,869 W | 23 | 37.04 kWh |
Peak sun hours: 4.51; annual output 1,308 kWh per kW. Source: state table derived from NREL PVWatts v8; check your exact address in NREL PVWatts.
Questions
How many peak sun hours does Illinois get?
4.51 kWh/m²/day on average, from NREL PVWatts v8 data.
How many solar panels for a house in Illinois?
Illinois averages 4.51 peak sun hours a day, so 1 kW of panels makes about 1,308 kWh a year. A home using 10 kWh a day needs about 2,956 W of panels.

