.solar-calc-header { text-align: center; margin-bottom: 30px; border-bottom: 2px solid #f0f0f0; padding-bottom: 20px; }
.solar-calc-header h2 { color: #2c3e50; margin: 0; font-size: 28px; }
.solar-calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 25px; }
.solar-calc-field { margin-bottom: 15px; }
.solar-calc-field label { display: block; font-weight: 600; margin-bottom: 8px; color: #444; font-size: 14px; }
.solar-calc-field input { width: 100%; padding: 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 16px; box-sizing: border-box; }
.solar-calc-field input:focus { border-color: #27ae60; outline: none; box-shadow: 0 0 5px rgba(39,174,96,0.2); }
.solar-calc-btn { background-color: #27ae60; color: white; border: none; padding: 15px 30px; border-radius: 5px; font-size: 18px; font-weight: bold; cursor: pointer; width: 100%; transition: background 0.3s ease; }
.solar-calc-btn:hover { background-color: #219150; }
.solar-calc-results { margin-top: 30px; padding: 20px; background-color: #f9fdf9; border: 1px solid #d4edda; border-radius: 5px; display: none; }
.solar-calc-results h3 { margin-top: 0; color: #155724; border-bottom: 1px solid #c3e6cb; padding-bottom: 10px; }
.solar-res-row { display: flex; justify-content: space-between; padding: 12px 0; border-bottom: 1px solid #eee; }
.solar-res-row:last-child { border-bottom: none; }
.solar-res-label { font-weight: 500; }
.solar-res-value { font-weight: bold; color: #27ae60; font-size: 18px; }
.solar-calc-article { margin-top: 40px; border-top: 2px solid #f0f0f0; padding-top: 30px; }
.solar-calc-article h3 { color: #2c3e50; font-size: 22px; margin-bottom: 15px; }
.solar-calc-article p { margin-bottom: 15px; color: #555; }
.solar-calc-article ul { margin-bottom: 15px; padding-left: 20px; }
.solar-calc-article li { margin-bottom: 8px; }
@media (max-width: 600px) { .solar-calc-grid { grid-template-columns: 1fr; } }
function calculateSolarROI() {
var cost = parseFloat(document.getElementById('sysCost').value);
var creditPercent = parseFloat(document.getElementById('fedCredit').value);
var sizeKW = parseFloat(document.getElementById('sysSize').value);
var hours = parseFloat(document.getElementById('sunHours').value);
var rate = parseFloat(document.getElementById('elecRate').value);
var maintenance = parseFloat(document.getElementById('maintCost').value);
if (isNaN(cost) || isNaN(sizeKW) || isNaN(hours) || isNaN(rate)) {
alert('Please enter valid numerical values for all required fields.');
return;
}
// Calculations
var netCost = cost * (1 – (creditPercent / 100));
var annualProduction = sizeKW * hours * 365;
var annualSavings = (annualProduction * rate) – maintenance;
var payback = 0;
if (annualSavings > 0) {
payback = netCost / annualSavings;
}
var totalSavings25 = annualSavings * 25;
var netProfit = totalSavings25 – netCost;
var roiPercent = (netProfit / netCost) * 100;
// Formatting Results
document.getElementById('resNetCost').innerText = '$' + netCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resProduction').innerText = Math.round(annualProduction).toLocaleString() + ' kWh';
document.getElementById('resAnnualSavings').innerText = '$' + annualSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
if (annualSavings Savings)';
} else {
document.getElementById('resPayback').innerText = payback.toFixed(1) + ' Years';
}
document.getElementById('resProfit').innerText = '$' + netProfit.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resROI').innerText = roiPercent.toFixed(1) + '%';
// Show results
document.getElementById('solarResults').style.display = 'block';
// Scroll to results
document.getElementById('solarResults').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}
Solar Panel ROI & Payback Calculator
Estimate your savings, payback period, and total return on investment for a solar energy system.
Your Estimated Investment Summary
Net System Cost (after tax credit):
$0.00
Annual Energy Production (kWh):
0 kWh
Estimated Annual Savings:
$0.00
Payback Period (Break-even):
0 Years
Estimated 25-Year Net Profit:
$0.00
25-Year ROI Percentage:
0%
How to Calculate Solar Panel ROI
Switching to solar energy is one of the most significant financial investments a homeowner can make. Understanding your Return on Investment (ROI) helps determine if the upfront cost is worth the long-term energy savings.
Key Factors in Solar Payback
- The Federal Solar Tax Credit (ITC): As of 2024, the federal government offers a 30% tax credit on the total cost of your solar installation. This drastically reduces your net investment.
- Solar Irradiance: The amount of peak sun hours your location receives directly impacts how much energy your panels produce. States like Arizona or California typically see faster ROI than northern states.
- Local Electricity Rates: The higher your current utility rates, the more money you save by generating your own power. If electricity prices rise (which they historically do), your ROI improves over time.
- System Size: Larger systems have higher upfront costs but often benefit from lower costs per watt and generate more total savings.
Understanding the Formula
To find your payback period, we use the following calculation: Net Cost / Annual Energy Savings = Payback Years. The average American solar installation reaches its break-even point in 6 to 10 years. Since most solar panels are warrantied for 25 years, the remaining 15+ years represent pure profit.
Example Scenario
Imagine a $20,000 system. After the 30% tax credit, your net cost is $14,000. If that system produces $1,800 worth of electricity annually and requires no maintenance, your payback period would be approximately 7.7 years. Over 25 years, you would save $45,000, resulting in a net profit of $31,000.