.calc-container { background: #ffffff; padding: 25px; border-radius: 12px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); margin-bottom: 30px; border-top: 5px solid #2ecc71; }
.calc-header { text-align: center; margin-bottom: 25px; }
.calc-header h2 { color: #27ae60; margin: 0; font-size: 28px; }
.input-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 20px; }
@media (max-width: 600px) { .input-grid { grid-template-columns: 1fr; } }
.input-group { display: flex; flex-direction: column; }
.input-group label { font-weight: 600; margin-bottom: 8px; color: #444; font-size: 14px; }
.input-group input { padding: 12px; border: 1px solid #ccc; border-radius: 6px; font-size: 16px; outline: none; transition: border-color 0.3s; }
.input-group input:focus { border-color: #2ecc71; }
.calc-btn { background: #2ecc71; color: white; border: none; padding: 15px 30px; border-radius: 6px; font-size: 18px; font-weight: bold; cursor: pointer; width: 100%; transition: background 0.3s; margin-top: 10px; }
.calc-btn:hover { background: #27ae60; }
.result-container { margin-top: 25px; padding: 20px; border-radius: 8px; background: #f9f9f9; display: none; border: 1px solid #eee; }
.result-item { display: flex; justify-content: space-between; padding: 10px 0; border-bottom: 1px solid #eee; }
.result-item:last-child { border-bottom: none; }
.result-label { font-weight: 500; color: #555; }
.result-value { font-weight: 700; color: #2ecc71; font-size: 18px; }
.highlight-result { background: #e8f8f0; border: 2px solid #2ecc71; border-radius: 8px; padding: 15px; text-align: center; margin-top: 15px; }
.highlight-result span { display: block; font-size: 24px; color: #27ae60; font-weight: 800; }
.solar-article { margin-top: 40px; }
.solar-article h2 { color: #2c3e50; font-size: 24px; border-bottom: 2px solid #2ecc71; padding-bottom: 10px; }
.solar-article h3 { color: #2c3e50; font-size: 20px; margin-top: 25px; }
.solar-article p { margin-bottom: 15px; text-align: justify; }
.solar-article ul { margin-bottom: 20px; }
.solar-article li { margin-bottom: 10px; }
.example-box { background: #f0f7ff; border-left: 5px solid #3498db; padding: 15px; margin: 20px 0; font-style: italic; }
function calculateSolarROI() {
// Get input values
var systemCost = parseFloat(document.getElementById("systemCost").value);
var taxCredit = parseFloat(document.getElementById("taxCredit").value);
var monthlyBill = parseFloat(document.getElementById("monthlyBill").value);
var elecRate = parseFloat(document.getElementById("elecRate").value);
var systemSize = parseFloat(document.getElementById("systemSize").value);
var sunHours = parseFloat(document.getElementById("sunHours").value);
// Validation
if (isNaN(systemCost) || isNaN(taxCredit) || isNaN(monthlyBill) || isNaN(elecRate) || isNaN(systemSize) || isNaN(sunHours)) {
alert("Please enter valid numbers in all fields.");
return;
}
// Calculation Logic
// 1. Net Cost after Incentives
var netCost = systemCost – (systemCost * (taxCredit / 100));
// 2. Annual Production (kWh)
// 0.78 is a standard de-rating factor for inverter loss, soilage, and wiring
var annualKwhProduced = systemSize * sunHours * 365 * 0.78;
// 3. Annual Savings ($)
var annualSavings = annualKwhProduced * elecRate;
// 4. Payback Period (Years)
var payback = netCost / annualSavings;
// 5. 25-Year Profit
// Accounting for 0.5% annual degradation
var totalSavings25Years = 0;
for (var i = 0; i 0 && isFinite(payback)) {
document.getElementById("paybackYears").innerText = payback.toFixed(1) + " Years";
} else {
document.getElementById("paybackYears").innerText = "Calculation Error";
}
document.getElementById("totalProfit").innerText = "$" + netProfit.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Scroll to results on mobile
if (window.innerWidth < 600) {
document.getElementById("solar-results").scrollIntoView({ behavior: 'smooth' });
}
}
Solar Panel ROI Calculator
Calculate your potential savings and payback period for a solar installation.
Net System Cost (after credits):
$0.00
Estimated Annual Production:
0 kWh
Estimated Annual Savings:
$0.00
Estimated Payback Period
0.0 Years
25-Year Net Profit:
$0.00
Is Solar Energy Worth It? Understanding Your Solar Panel ROI
Transitioning to solar energy is one of the most significant financial decisions a homeowner can make. While the environmental benefits are clear, the financial return on investment (ROI) is often the primary driver for installation. Using our Solar Panel ROI Calculator, you can determine exactly how long it will take for your system to pay for itself and how much you stand to gain over the system's 25-year lifespan.
How Solar ROI is Calculated
Calculating the ROI of solar panels involves more than just subtracting your bill from the cost. To get an accurate picture, we analyze several key variables:
- The Net System Cost: This is the gross price of your solar installation minus federal tax credits (like the Investment Tax Credit or ITC), state rebates, and local incentives.
- Solar Production: Based on your system size (in kW) and the average daily peak sun hours in your geographic location, we estimate how much electricity your panels will generate annually.
- Offset Value: We compare your solar production to your current utility rate. If you have "Net Metering" in your area, every kWh you send back to the grid is credited at the full retail rate.
- Payback Period: This is the "break-even" point where the cumulative energy savings equal the initial net cost of the system.
Example Calculation: If a homeowner in California installs an $18,000 system and receives a 30% Federal Tax Credit, their net cost is $12,600. If that system saves them $1,800 a year in electricity bills, the payback period is exactly 7 years ($12,600 / $1,800).
Factors That Impact Your Savings
1. Local Electricity Rates
Solar is most profitable in regions with high electricity rates. If you pay $0.20 per kWh, your panels are twice as valuable as they would be in an area where electricity costs only $0.10 per kWh.
2. Peak Sun Hours
Not all sunlight is created equal. "Peak sun hours" refers to the intensity of the sun. Arizona may receive 6+ peak hours, while Washington state might only average 3.5. This directly affects how many panels you need to achieve your savings goals.
3. Maintenance and Degradation
Modern Tier-1 solar panels are incredibly durable, but they do lose a small amount of efficiency each year (typically 0.5%). Our calculator accounts for standard production efficiency to ensure your 25-year profit projection is realistic.
Maximizing Your Investment
To ensure you get the best ROI, consider the following steps:
- Check for Local Incentives: Beyond the federal 30% credit, many utility companies offer performance-based incentives (PBIs) or SRECs (Solar Renewable Energy Credits).
- Optimize Roof Placement: South-facing roofs with a 30-45 degree tilt generally provide the highest energy yield in the Northern Hemisphere.
- Energy Efficiency First: Before installing solar, reduce your overall load by upgrading to LED lighting and high-efficiency appliances. This allows you to buy a smaller, cheaper solar system.