Lasik Cost Calculator

Solar Panel ROI & Payback Calculator

Estimate your solar savings and break-even point in seconds.

Net System Cost

$0

Annual Savings

$0

Payback Period

0 Years

25-Year Profit

$0

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How Solar ROI is Calculated

Calculating the Return on Investment (ROI) for solar panels involves understanding both the upfront costs and the long-term utility savings. Most homeowners see a payback period between 6 and 10 years, depending on local electricity rates and available state incentives.

The Key Factors:

• Federal Solar Tax Credit (ITC): As of 2024, the federal government offers a 30% tax credit on the total cost of your solar installation, significantly reducing your net investment.
• Solar Insultation: This refers to how much sunlight your specific location receives. A house in Arizona will generate more electricity per panel than one in Washington state.
• Utility Rates: The higher your current electric bill, the more money you save by switching to solar. If your utility company uses "Net Metering," you can even get credit for excess energy you send back to the grid.
• System Degradation: Most solar panels are warrantied for 25 years. While they lose a tiny bit of efficiency each year (usually 0.5%), they continue providing "free" power long after the system has paid for itself.

Example Calculation:

If you install a 6kW system for $18,000, your 30% tax credit reduces the cost to $12,600. If that system produces 8,700 kWh per year and your rate is $0.16/kWh, you save $1,392 annually. Your payback period would be roughly 9 years, leaving you with 16+ years of pure profit.

function calculateSolarROI() { var size = parseFloat(document.getElementById('systemSize').value); var cost = parseFloat(document.getElementById('systemCost').value); var rate = parseFloat(document.getElementById('electricRate').value); var taxCreditPct = parseFloat(document.getElementById('taxCredit').value); var sunHours = parseFloat(document.getElementById('sunHours').value); if (isNaN(size) || isNaN(cost) || isNaN(rate) || isNaN(taxCreditPct) || isNaN(sunHours)) { alert("Please enter valid numbers in all fields."); return; } // 1. Calculate Net Cost after Incentives var netCost = cost – (cost * (taxCreditPct / 100)); // 2. Calculate Annual Production (kW * hours * efficiency factor) // We use a standard 0.85 derate factor for inverter loss, wiring, and dirt var annualProduction = size * sunHours * 0.85; // 3. Annual Savings ($) var annualSavings = annualProduction * rate; // 4. Payback Period (Years) var payback = netCost / annualSavings; // 5. 25-Year ROI (Cumulative savings – net cost) // Accounting for slight 0.5% degradation per year var totalSavings = 0; var currentProduction = annualProduction; for (var i = 0; i < 25; i++) { totalSavings += currentProduction * rate; currentProduction *= 0.995; // 0.5% degradation } var lifetimeROI = totalSavings – netCost; // Display Results document.getElementById('netCost').innerHTML = '$' + netCost.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0}); document.getElementById('annualSavings').innerHTML = '$' + annualSavings.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0}); document.getElementById('paybackPeriod').innerHTML = payback.toFixed(1) + ' Years'; document.getElementById('lifetimeROI').innerHTML = '$' + lifetimeROI.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0}); document.getElementById('results-area').style.display = 'block'; // Scroll to results smoothly document.getElementById('results-area').scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }