Solar Payback Calculator

How to use this calculator

Enter your planned system size in kW, pick the sun exposure that best matches your region, and enter your electricity rate from a recent utility bill. The calculator estimates system cost, how much electricity it will produce in a year, and how many years it takes for savings to pay back that cost.

How this is calculated

System cost is your size in kW times a national installed price-per-watt range. Annual production is your size times a rule-of-thumb output factor for your sun exposure (kWh produced per kW of installed capacity per year). Annual savings is that production times your electricity rate, and payback period is cost divided by annual savings.

Example

A 6 kW system in an average-sun region at $0.17/kWh costs $15,000–$21,000, produces about 8,400 kWh a year, saves about $1,430 a year, and pays back in roughly 11–15 years.

Estimate only. Production depends heavily on your roof's orientation, shading, and local weather, so treat this as a rough planning range and get a site-specific production estimate from an installer. The federal Section 25D Residential Clean Energy Credit (30% of cost) expired for systems placed in service after December 31, 2025, and is not included in this estimate. State, utility, or net-metering programs vary by location and aren't included either.