Dc Income Tax Calculator

Solar Panel ROI & Payback Calculator

Your Solar Projection:

Net System Cost:

Annual Savings:

Payback Period:

25-Year Net Profit:

function calculateSolarROI() { var cost = parseFloat(document.getElementById('systemCost').value); var credit = parseFloat(document.getElementById('taxCredit').value); var bill = parseFloat(document.getElementById('monthlyBill').value); var offset = parseFloat(document.getElementById('energyOffset').value); if (isNaN(cost) || isNaN(credit) || isNaN(bill) || isNaN(offset)) { alert('Please enter valid numbers in all fields.'); return; } // Logic var netCost = cost – (cost * (credit / 100)); var monthlySavings = bill * (offset / 100); var annualSavings = monthlySavings * 12; var paybackYears = netCost / annualSavings; // Assume 3% annual electricity price increase for lifetime savings var totalSavings = 0; var currentAnnualSavings = annualSavings; for (var i = 0; i < 25; i++) { totalSavings += currentAnnualSavings; currentAnnualSavings *= 1.03; } var netProfit = totalSavings – netCost; // Display results document.getElementById('netCostDisplay').innerText = '$' + netCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('annualSavingsDisplay').innerText = '$' + annualSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('paybackDisplay').innerText = paybackYears.toFixed(1) + ' Years'; document.getElementById('lifetimeSavingsDisplay').innerText = '$' + netProfit.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('solarResult').style.display = 'block'; }

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Understanding Your Solar Investment Return

Switching to solar energy is one of the most significant financial and environmental decisions a homeowner can make. This calculator helps you determine the Return on Investment (ROI) and the Payback Period—the amount of time it takes for your electricity savings to cover the initial cost of the system.

Key Factors in Solar Math

• The Federal Investment Tax Credit (ITC): Currently, the US federal government offers a 30% tax credit on residential solar installations. This significantly reduces the "Net Cost" of your system.
• Energy Offset: This is how much of your current electricity usage will be replaced by solar. Most systems are designed for 100% offset, but roof space or shading might limit this.
• Electricity Inflation: Utility rates historically rise by about 2-4% annually. Solar "locks in" your rate, meaning your savings actually grow every year as grid power becomes more expensive.

A Realistic Example

Imagine you install a system for $25,000. After the 30% Federal Tax Credit, your net cost drops to $17,500. If your current monthly bill is $200 and your solar system covers 100% of your needs, you are saving $2,400 per year.

In this scenario, your payback period would be roughly 7.3 years. Since solar panels are typically warrantied for 25 years, you would enjoy over 17 years of "free" electricity, resulting in tens of thousands of dollars in pure profit.

Why the Payback Period Matters

The shorter the payback period, the better the investment. Most residential solar installations in the United States have a payback period between 6 and 10 years. Factors like local state rebates, SREC (Solar Renewable Energy Certificate) markets, and high local utility rates can accelerate this timeline significantly.