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Solar Panel Savings & ROI Calculator

Your Solar Estimation

Monthly Production
0 kWh
Monthly Savings
$0.00
Payback Period
0 Years
25-Year Net Profit
$0.00
function calculateSolarSavings() { var bill = parseFloat(document.getElementById('monthlyBill').value); var size = parseFloat(document.getElementById('systemSize').value); var hours = parseFloat(document.getElementById('sunHours').value); var rate = parseFloat(document.getElementById('elecRate').value); var cost = parseFloat(document.getElementById('installCost').value); if (isNaN(bill) || isNaN(size) || isNaN(hours) || isNaN(rate) || isNaN(cost)) { alert("Please fill in all fields with valid numbers."); return; } // Monthly production in kWh var monthlyProduction = size * hours * 30; // Value of that electricity var potentialMonthlySavings = monthlyProduction * rate; // You can't save more than you spend (assuming no net-metering payout for excess) var actualMonthlySavings = potentialMonthlySavings > bill ? bill : potentialMonthlySavings; var yearlySavings = actualMonthlySavings * 12; var paybackYears = cost / yearlySavings; var lifetimeSavings = (yearlySavings * 25) – cost; document.getElementById('resProduction').innerText = monthlyProduction.toFixed(0) + " kWh"; document.getElementById('resSavings').innerText = "$" + actualMonthlySavings.toFixed(2); document.getElementById('resPayback').innerText = paybackYears.toFixed(1) + " Years"; document.getElementById('resProfit').innerText = "$" + lifetimeSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('solar-results').style.display = 'block'; }

Understanding Your Solar Investment

Deciding to switch to solar energy is a significant financial and environmental decision. This Solar Panel Savings Calculator is designed to help homeowners estimate the Return on Investment (ROI) by looking at sunlight exposure, utility rates, and installation costs.

How the Calculation Works

To determine how much you can save, we use several key metrics:

  • System Production: Calculated as (System Size in kW) × (Peak Sun Hours) × (30 Days). This estimates how much energy your panels generate monthly.
  • Monthly Savings: We multiply your production by your current electricity rate. If your panels produce more than you use, the savings are typically capped at your current bill amount, unless your utility offers cash-back net metering.
  • Payback Period: This is the "break-even" point, calculated by dividing the total installation cost by your annual energy savings.

Example Scenario

Imagine a homeowner in California with the following stats:

System Size: 6 kW
Daily Sunlight: 5 hours
Electricity Rate: $0.22/kWh
Installation Cost: $15,000 (after incentives)

In this case, the system produces 900 kWh per month. At a rate of $0.22, that is a savings of $198 per month. The payback period would be approximately 6.3 years, leaving over 18 years of virtually free electricity.

Factors That Influence Your Savings

While this calculator provides a strong estimate, your actual results may vary based on:

  1. Roof Orientation: South-facing roofs in the northern hemisphere typically produce the most energy.
  2. Shading: Trees or nearby buildings can reduce efficiency.
  3. Local Incentives: Federal tax credits (like the ITC) and local rebates can slash installation costs by 30% or more.
  4. Utility Net Metering: Some utilities allow you to sell excess power back to the grid at retail rates, while others use wholesale rates.

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