State

How much solar do I need in Illinois?

Modern house with rooftop solar panels and a straight concrete driveway at golden hour

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 usePanel watts400 W panelsBattery for 1 day
5 kWh/day1,478 W46.17 kWh
10 kWh/day2,956 W812.35 kWh
20 kWh/day5,913 W1524.69 kWh
30 kWh/day8,869 W2337.04 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.