Calculate your potential savings and investment return on solar energy.
Net System Cost
$0.00
Payback Period
0.0 Years
25-Year Savings
$0.00
Lifetime ROI
0%
Understanding Your Solar Investment Return
Switching to solar energy is one of the most significant financial decisions a homeowner can make. Beyond the environmental benefits, the Return on Investment (ROI) often outperforms traditional market investments. This calculator helps you determine how quickly your energy savings will cover the initial installation costs.
Key Factors That Determine Solar ROI
The Federal Investment Tax Credit (ITC): Currently, homeowners can deduct a significant percentage (30% through 2032) of their solar installation costs from their federal taxes. This drastically lowers the "Net Cost."
Solar Irradiance: The number of "Peak Sun Hours" your roof receives directly correlates to energy production. A home in Arizona will typically reach its ROI faster than a home in Washington state.
Local Electricity Rates: Solar panels are essentially a hedge against rising utility costs. If your local utility rates are high (e.g., $0.25/kWh), your panels save you more money every month compared to a region with cheap power.
System Degradation: Quality solar panels are warrantied for 25 years. They typically lose about 0.5% efficiency per year, which is accounted for in our lifetime savings calculation.
Is Solar a Good Investment in 2024?
For most homeowners with an unshaded roof and a monthly electricity bill over $100, solar is a high-yield investment. The average American solar payback period is between 6 to 10 years. Since systems last 25-30 years, you effectively get 15-20 years of "free" electricity.
Pro Tip: When calculating your ROI, don't forget to check for local state rebates or SREC (Solar Renewable Energy Certificate) programs, which can further accelerate your payback period beyond the federal tax credit.
function calculateSolarROI() {
// Get Input Values
var cost = parseFloat(document.getElementById('solarCost').value);
var taxCreditPercent = parseFloat(document.getElementById('taxCredit').value);
var systemSize = parseFloat(document.getElementById('systemSize').value);
var sunHours = parseFloat(document.getElementById('sunHours').value);
var rate = parseFloat(document.getElementById('elecRate').value);
var inflation = parseFloat(document.getElementById('inflation').value) / 100;
// Validate inputs
if (isNaN(cost) || isNaN(systemSize) || isNaN(sunHours) || isNaN(rate)) {
alert("Please enter valid numerical values.");
return;
}
// 1. Calculate Net Cost
var taxCreditAmount = cost * (taxCreditPercent / 100);
var netCost = cost – taxCreditAmount;
// 2. Calculate Annual Energy Production (kWh)
// Formula: Size (kW) * Sun Hours * 365 * 0.78 (Standard 22% derate factor for inverter losses/soiling)
var annualProduction = systemSize * sunHours * 365 * 0.78;
// 3. Calculate First Year Savings
var yearOneSavings = annualProduction * rate;
// 4. Calculate Payback Period and 25-Year Cumulative Savings
var cumulativeSavings = 0;
var paybackPeriod = 0;
var currentRate = rate;
var currentProduction = annualProduction;
var foundPayback = false;
for (var year = 1; year = netCost) {
// Simple interpolation for partial year payback
var remainingBeforeYear = netCost – (cumulativeSavings – yearlySavings);
paybackPeriod = (year – 1) + (remainingBeforeYear / yearlySavings);
foundPayback = true;
}
// Apply inflation to electricity and degradation to panels (0.5% degradation)
currentRate = currentRate * (1 + inflation);
currentProduction = currentProduction * 0.995;
}
// Handle case where system never pays back
if (!foundPayback) {
paybackPeriod = netCost / yearOneSavings;
}
// 5. Calculate ROI
var totalProfit = cumulativeSavings – netCost;
var roiTotal = (totalProfit / netCost) * 100;
// Display Results
document.getElementById('resNetCost').innerText = "$" + netCost.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0});
document.getElementById('resPayback').innerText = paybackPeriod.toFixed(1) + " Years";
document.getElementById('resSavings').innerText = "$" + cumulativeSavings.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0});
document.getElementById('resROI').innerText = roiTotal.toFixed(0) + "%";
document.getElementById('solar-results').style.display = 'block';
// Smooth scroll to results
document.getElementById('solar-results').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}