Estimate how long it will take for your solar energy system to pay for itself through utility savings.
Net System Cost:
Estimated Annual Savings:
Payback Period:
25-Year Total Return:
Understanding Your Solar ROI
The Solar Payback Period is the amount of time it takes for the electricity bill savings generated by a solar PV system to equal the initial cost of the installation. For most American homeowners, this period typically falls between 6 and 10 years.
How We Calculate Your Results
To determine your financial break-even point, we use the following formula:
Net Cost: Total Installation Cost minus the Federal Solar Tax Credit (ITC) and local utility rebates.
Annual Savings: Your total annual energy production in kilowatt-hours (kWh) multiplied by your current utility electricity rate.
Payback Period: Net Cost divided by Annual Savings.
Example Calculation
Imagine you install a system costing $20,000. After applying the 30% Federal Tax Credit ($6,000), your net cost is $14,000. If that system produces 10,000 kWh per year and your utility charges $0.16 per kWh, you save $1,600 annually. Your payback period would be 14,000 / 1,600 = 8.75 years.
Factors That Speed Up Payback
Rising Electricity Rates: As utility prices go up, your solar-generated power becomes more valuable.
SREC Incentives: In some states, you can sell "Solar Renewable Energy Certificates" for additional cash.
Optimized Placement: South-facing roofs with no shade produce the most energy, shortening the ROI window.
function calculateSolarROI() {
var totalCost = parseFloat(document.getElementById("totalCost").value);
var taxCredit = parseFloat(document.getElementById("taxCredit").value);
var annualProduction = parseFloat(document.getElementById("annualProduction").value);
var electricityRate = parseFloat(document.getElementById("electricityRate").value);
if (isNaN(totalCost) || isNaN(taxCredit) || isNaN(annualProduction) || isNaN(electricityRate) || annualProduction <= 0 || electricityRate <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
var netCost = totalCost – taxCredit;
if (netCost < 0) netCost = 0;
var annualSavings = annualProduction * electricityRate;
var paybackPeriod = netCost / annualSavings;
var twentyFiveYearSavings = (annualSavings * 25) – netCost;
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document.getElementById("annualSavingsDisplay").innerText = "$" + annualSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("paybackPeriodDisplay").innerText = paybackPeriod.toFixed(1) + " Years";
document.getElementById("longTermROI").innerText = "$" + twentyFiveYearSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("solarResults").style.display = "block";
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