Solar Payback & ROI Calculator
Estimate the simple payback period and lifetime net savings of a residential solar install from system cost, incentives, monthly bill, and bill offset.
- Enter system cost Input the total installed System cost in dollars before any incentives.
- Set incentives Enter the Incentives percentage (default 30 for the federal ITC) covering federal, state, or utility credits and rebates.
- Enter your electric bill Input your average Monthly electric bill in dollars.
- Set bill offset and calculate Enter the Bill offset percentage the system covers (default 90) and press Calculate to get net cost, annual savings, simple payback, and 25-year net savings.
What is the payback period on a $25,000 solar system?
With the default 30 percent incentive, a $25,000 system has a net cost of $17,500. If your monthly bill is $200 and the array offsets 90 percent, annual savings are about $2,160, giving a simple payback of roughly 8.1 years. The calculator divides net cost by annual savings, so lower bills or smaller offsets stretch the payback longer.
How are solar incentives applied to the cost?
The calculator multiplies system cost by one minus the incentive percentage, so a 30 percent incentive on a $20,000 system yields a $14,000 net cost. The 30 percent default reflects the federal ITC per IRS Form 5695. Incentive amounts change and may stack with state or utility rebates, so confirm the current rate before relying on the result.
Does the solar payback calculator account for rate inflation?
No. It computes a simple, undiscounted payback and 25-year net savings, ignoring electricity-rate inflation, panel degradation, financing, and the time value of money. Annual savings are held flat at monthly bill times 12 times the offset percentage. Treat the output as a rough comparison rather than a full financial model.