Estimate your savings and calculate how many years it will take for your solar energy system to pay for itself.
Net System Cost:
Estimated Payback Period:
Year 1 Savings:
Total 25-Year Savings:
25-Year Net Profit (ROI):
How Solar ROI is Calculated
Calculating the Return on Investment (ROI) for solar panels involves more than just subtracting your bill from the cost. To get an accurate picture, you must account for the Federal Solar Tax Credit (ITC), state rebates, and the rising cost of electricity from traditional utilities.
Our calculator uses the following logic:
Net Investment: The gross cost of installation minus upfront incentives and tax credits.
Annual Savings: Your monthly bill multiplied by your offset percentage, compounded annually by the expected utility inflation rate.
Degradation: We factor in a standard 0.5% annual loss in panel efficiency to ensure the numbers remain realistic over 25 years.
Typical Solar Payback Example
If a homeowner installs a system for $18,000 and receives a 30% federal tax credit ($5,400), their net cost is $12,600. If their electricity bill is $150/month and the solar covers 100% of it, they save $1,800 in the first year. With utility prices rising at 3.5% annually, the payback period typically falls between 6 to 9 years.
Factors Influencing Your Results
Several variables can shift your "Break-even" point:
Sun Exposure: Homes in Arizona will reach ROI faster than those in Washington due to peak sun hours.
Local Utility Rates: The more expensive your current electricity is, the more you save by producing your own.
Net Metering: If your state allows you to sell excess energy back to the grid at retail rates, your ROI improves significantly.
function calculateSolarROI() {
var systemCost = parseFloat(document.getElementById('systemCost').value);
var incentives = parseFloat(document.getElementById('incentives').value);
var monthlyBill = parseFloat(document.getElementById('monthlyBill').value);
var offset = parseFloat(document.getElementById('offset').value) / 100;
var inflation = parseFloat(document.getElementById('inflation').value) / 100;
var degradation = parseFloat(document.getElementById('degradation').value) / 100;
if (isNaN(systemCost) || isNaN(incentives) || isNaN(monthlyBill)) {
alert("Please enter valid numbers in all fields.");
return;
}
var netCost = systemCost – incentives;
var yearOneSavings = (monthlyBill * 12) * offset;
var cumulativeSavings = 0;
var paybackYear = -1;
var totalSavings25 = 0;
for (var year = 1; year = netCost) {
paybackYear = year;
}
if (year === 25) {
totalSavings25 = cumulativeSavings;
}
}
var netProfit25 = totalSavings25 – netCost;
// Display Results
document.getElementById('solar-result').style.display = 'block';
document.getElementById('netCostDisplay').innerText = '$' + netCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
if (paybackYear !== -1) {
document.getElementById('paybackDisplay').innerText = paybackYear + ' Years';
} else {
document.getElementById('paybackDisplay').innerText = 'Over 25 Years';
}
document.getElementById('yearOneSavings').innerText = '$' + yearOneSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('totalSavings').innerText = '$' + totalSavings25.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('netProfit').innerText = '$' + netProfit25.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Smooth scroll to result
document.getElementById('solar-result').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}