Calculate the financial return on your residential solar investment.
Net System Cost (After Incentives)$0.00
Estimated Payback Period0 Years
Total Lifetime Savings (Net)$0.00
Return on Investment (ROI)0%
How Solar ROI is Calculated
Calculating the Return on Investment (ROI) for solar panels involves comparing the upfront net cost of the system against the accumulated energy savings over its lifespan. The Federal Solar Tax Credit (ITC), currently at 30%, significantly reduces the initial investment. Our calculator takes your total gross cost, subtracts these incentives, and then divides that net cost by your annual electricity savings to find the "Break-even Point."
Key Factors Influencing Your Results
Sunlight Exposure: Houses in regions with high solar irradiance (like Arizona or California) will generate more kWh per panel, speeding up the ROI.
Utility Rates: The more expensive your local grid electricity is, the more money you save every time you generate your own power.
Incentives: Beyond federal credits, many states offer SRECs (Solar Renewable Energy Certificates) or local rebates that can further decrease the payback period.
Net Metering: If your utility allows you to sell excess power back to the grid at retail rates, your ROI will be substantially higher.
Example Scenario
If you purchase a solar system for $20,000 and qualify for the 30% Federal Tax Credit, your net investment is $14,000. If that system eliminates a $150 monthly power bill, you save $1,800 annually. Without accounting for rising energy costs, your payback period would be approximately 7.7 years. Over a 25-year lifespan, your total savings would exceed $45,000, representing a massive ROI compared to traditional investments.
function calculateSolarROI() {
var grossCost = parseFloat(document.getElementById("solarCost").value);
var incentivePct = parseFloat(document.getElementById("solarIncentive").value) / 100;
var monthlyBill = parseFloat(document.getElementById("monthlySavings").value);
var coverage = parseFloat(document.getElementById("billCoverage").value) / 100;
var maintenance = parseFloat(document.getElementById("annualMaintenance").value);
var lifespan = parseFloat(document.getElementById("systemLife").value);
if (isNaN(grossCost) || isNaN(monthlyBill) || grossCost <= 0) {
alert("Please enter valid positive numbers for system cost and monthly savings.");
return;
}
// Logic for Net Cost
var netCost = grossCost * (1 – incentivePct);
// Logic for Annual Savings
var annualSavings = (monthlyBill * 12 * coverage) – maintenance;
if (annualSavings <= 0) {
document.getElementById("resPayback").innerText = "Never";
document.getElementById("resLifetime").innerText = "Negative Savings";
document.getElementById("resROI").innerText = "0%";
} else {
// Logic for Payback Period
var payback = netCost / annualSavings;
// Logic for Lifetime Total Savings
var totalSavings = (annualSavings * lifespan) – netCost;
// Logic for ROI
var roi = (totalSavings / netCost) * 100;
// Display results
document.getElementById("resNetCost").innerText = "$" + netCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resPayback").innerText = payback.toFixed(1) + " Years";
document.getElementById("resLifetime").innerText = "$" + totalSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resROI").innerText = roi.toFixed(1) + "%";
}
document.getElementById("solar-results").style.display = "block";
}