Calculate your potential energy savings and payback period instantly.
Avg. home uses 6-10kW
Gross price before incentives
Check your local utility bill
US average is 4 to 6 hours
Federal ITC is currently 30%
Calculation Summary
Net System Cost
$0
Annual Production
0 kWh
Annual Savings
$0
Payback Period
0 Years
Estimated 25-Year Net Savings: $0
Understanding Your Solar Investment
Switching to solar energy is one of the most effective ways for homeowners to reduce their carbon footprint while simultaneously cutting monthly utility costs. This calculator helps you determine the Return on Investment (ROI) by analyzing your local sunlight conditions and available incentives.
Key Factors in Solar Calculations
The Federal Solar Tax Credit (ITC): Under the Inflation Reduction Act, homeowners can claim a 30% credit on their federal taxes for the cost of a solar photovoltaic (PV) system. This significantly lowers the "Net Cost."
Solar Insolation (Sun Hours): This isn't just daylight; it's the intensity of the sun. Southern states like Arizona may see 6+ hours, while Northern states might average 3.5 to 4.
Derate Factor: Solar panels don't operate at 100% efficiency due to heat, wiring losses, and inverter conversion. Our calculator uses a standard 0.78 derate factor to provide realistic production estimates.
Real-World Example
Imagine a homeowner in California with a $20,000 system quote for an 8kW array. After the 30% federal tax credit, the net cost drops to $14,000. If the area receives 5 sun hours per day and the utility rate is $0.22/kWh, the system generates roughly 11,388 kWh annually. This results in $2,505 in yearly savings, leading to a payback period of just 5.6 years. Over 25 years, the total profit exceeds $48,000.
Maintenance and Longevity
Modern solar panels are typically warrantied for 25 years. While the inverter may need replacement around year 15, the maintenance costs are remarkably low, usually just involving occasional cleaning to remove dust or debris that blocks sunlight.
function calculateSolarSavings() {
// Get Input Values
var systemSize = parseFloat(document.getElementById('systemSize').value);
var totalCost = parseFloat(document.getElementById('totalCost').value);
var elecRate = parseFloat(document.getElementById('elecRate').value);
var sunHours = parseFloat(document.getElementById('sunHours').value);
var taxCreditPerc = parseFloat(document.getElementById('taxCreditPerc').value);
// Validation
if (isNaN(systemSize) || isNaN(totalCost) || isNaN(elecRate) || isNaN(sunHours) || isNaN(taxCreditPerc)) {
alert("Please enter valid numeric values in all fields.");
return;
}
// Constants
var derateFactor = 0.78; // Standard system losses (heat, wiring, inverter)
var systemLifespan = 25; // Standard warranty period
// Logic
var netCost = totalCost * (1 – (taxCreditPerc / 100));
// Annual Production (kWh) = Size (kW) * Daily Sun Hours * 365 days * Derate Factor
var annualGen = systemSize * sunHours * 365 * derateFactor;
// Annual Financial Savings
var annualSavings = annualGen * elecRate;
// Payback Period (Years)
var paybackPeriod = netCost / annualSavings;
// 25-Year Total Savings (Accounting for Net Cost)
var totalLifetimeSavings = (annualSavings * systemLifespan) – netCost;
// Display Results
document.getElementById('solar-results').style.display = 'block';
document.getElementById('resNetCost').innerText = '$' + netCost.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0});
document.getElementById('resAnnualGen').innerText = Math.round(annualGen).toLocaleString() + ' kWh';
document.getElementById('resAnnualSavings').innerText = '$' + annualSavings.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0});
document.getElementById('resPayback').innerText = paybackPeriod.toFixed(1) + ' Years';
document.getElementById('resTotalSavings').innerText = '$' + totalLifetimeSavings.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0});
// Scroll to results
document.getElementById('solar-results').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}