How Much Do Solar Panels Cost in Idaho?

$21,142

A 7.1 kW system sized for 865 kWh a month costs about $21,142 in Idaho at $2.99 per watt before incentives. At Idaho’s average electricity rate it saves about $1,350 a year, for a simple payback of 15.7 years, assuming every kWh is credited at the retail rate. If your utility pays less for power you export than it charges you, the payback will be longer.

Solar cost and payback in Idaho by monthly electricity use

Usage per monthSystem costSavings per yearPayback
500 kWh$12,221$78115.7 years
865 kWh$21,142$1,35015.7 years
1,000 kWh$24,441$1,56115.7 years
1,500 kWh$36,662$2,34215.7 years
2,000 kWh$48,883$3,12215.7 years

Adjust the numbers

The calculator below is pre-filled with the numbers above. Change any value to match your project.

Solar cost & payback
kWh
$/W
Leave at 0 to use the average for your state. Divide a quote by its watts to compare.
Estimated cost$21,142
System size
7.1 kW (covers 100% of use)
Price per watt
$2.99 (Idaho average)
Savings per year
$1,350
Simple payback
15.7 years

How it is calculated

The system is sized to cover 100% of your yearly use with your state’s solar production (NREL PVWatts). Cost = system watts × the average installed price per watt in your state from EnergySage (2026), or the U.S. average of $2.60/W where no state figure is available.

Yearly savings = the electricity the system produces × your state’s average residential rate (EIA, March 2026). Simple payback = cost ÷ yearly savings. It assumes full credit for every kWh (net metering) and ignores panel degradation and future rate changes.

Open the full solar cost & payback calculator for other shapes, a worked example and FAQs.

Other common sizes