Solar Savings Calculator
Estimate your potential financial savings by installing a solar energy system. This calculator helps you understand the long-term benefits based on your current electricity usage, system costs, and local conditions.
.solar-savings-calculator {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f9f9f9;
padding: 25px;
border-radius: 10px;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
max-width: 700px;
margin: 30px auto;
border: 1px solid #e0e0e0;
}
.solar-savings-calculator h2 {
color: #2c3e50;
text-align: center;
margin-bottom: 20px;
font-size: 1.8em;
}
.solar-savings-calculator p {
color: #555;
text-align: center;
margin-bottom: 25px;
line-height: 1.6;
}
.solar-savings-calculator .form-group {
margin-bottom: 18px;
display: flex;
flex-direction: column;
}
.solar-savings-calculator label {
font-weight: bold;
margin-bottom: 8px;
color: #34495e;
font-size: 0.95em;
}
.solar-savings-calculator input[type="number"] {
width: calc(100% – 20px);
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 1em;
box-sizing: border-box;
transition: border-color 0.3s ease;
}
.solar-savings-calculator input[type="number"]:focus {
border-color: #28a745;
outline: none;
box-shadow: 0 0 5px rgba(40, 167, 69, 0.3);
}
.solar-savings-calculator small {
color: #777;
font-size: 0.85em;
margin-top: 5px;
}
.solar-savings-calculator button {
background-color: #28a745;
color: white;
padding: 14px 25px;
border: none;
border-radius: 6px;
cursor: pointer;
font-size: 1.1em;
font-weight: bold;
display: block;
width: 100%;
margin-top: 25px;
transition: background-color 0.3s ease, transform 0.2s ease;
}
.solar-savings-calculator button:hover {
background-color: #218838;
transform: translateY(-2px);
}
.calculator-results {
margin-top: 30px;
padding: 20px;
background-color: #e6f7ee;
border: 1px solid #c3e6cb;
border-radius: 8px;
color: #218838;
font-size: 1.1em;
line-height: 1.8;
}
.calculator-results h3 {
color: #28a745;
margin-top: 0;
margin-bottom: 15px;
font-size: 1.5em;
text-align: center;
}
.calculator-results p {
margin-bottom: 10px;
text-align: left;
color: #333;
}
.calculator-results p strong {
color: #28a745;
}
function calculateSolarSavings() {
var monthlyElectricityBill = parseFloat(document.getElementById("monthlyElectricityBill").value);
var electricityCostPerKWH = parseFloat(document.getElementById("electricityCostPerKWH").value);
var solarSystemSize = parseFloat(document.getElementById("solarSystemSize").value);
var annualKWHPerKW = parseFloat(document.getElementById("annualKWHPerKW").value);
var solarSystemCost = parseFloat(document.getElementById("solarSystemCost").value);
var federalTaxCredit = parseFloat(document.getElementById("federalTaxCredit").value);
var electricityInflationRate = parseFloat(document.getElementById("electricityInflationRate").value);
var systemDegradationRate = parseFloat(document.getElementById("systemDegradationRate").value);
var systemLifespan = parseInt(document.getElementById("systemLifespan").value);
var resultsDiv = document.getElementById("solarResults");
resultsDiv.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(monthlyElectricityBill) || monthlyElectricityBill < 0 ||
isNaN(electricityCostPerKWH) || electricityCostPerKWH <= 0 ||
isNaN(solarSystemSize) || solarSystemSize <= 0 ||
isNaN(annualKWHPerKW) || annualKWHPerKW <= 0 ||
isNaN(solarSystemCost) || solarSystemCost < 0 ||
isNaN(federalTaxCredit) || federalTaxCredit 100 ||
isNaN(electricityInflationRate) || electricityInflationRate < 0 ||
isNaN(systemDegradationRate) || systemDegradationRate 100 ||
isNaN(systemLifespan) || systemLifespan < 1) {
resultsDiv.innerHTML = "Please enter valid positive numbers for all fields. Electricity cost per kWh and system size must be greater than zero.";
return;
}
// Convert percentages to decimals
federalTaxCredit /= 100;
electricityInflationRate /= 100;
systemDegradationRate /= 100;
// 1. Calculate Net System Cost
var netSystemCost = solarSystemCost * (1 – federalTaxCredit);
// 2. Calculate Annual Electricity Consumption (kWh)
var annualKWHConsumption = (monthlyElectricityBill / electricityCostPerKWH) * 12;
// 3. Calculate Estimated Annual Solar Production (Year 1)
var annualSolarProductionYear1 = solarSystemSize * annualKWHPerKW;
// 4. Calculate Year 1 Electricity Savings
// Savings are based on the electricity produced by solar, valued at current electricity cost.
// We assume the user consumes all generated electricity or gets fair credit for excess.
var annualElectricitySavingsYear1 = annualSolarProductionYear1 * electricityCostPerKWH;
// 5. Calculate Total Savings Over System Lifespan and Payback Period
var cumulativeSavings = 0;
var currentElectricityCost = electricityCostPerKWH;
var currentSolarProduction = annualSolarProductionYear1;
var paybackPeriod = "Beyond system lifespan";
var totalSavingsOverLifespan = 0;
for (var year = 1; year = netSystemCost && paybackPeriod === "Beyond system lifespan") {
paybackPeriod = year;
}
// Adjust for inflation and degradation for the next year
currentElectricityCost *= (1 + electricityInflationRate);
currentSolarProduction *= (1 – systemDegradationRate);
}
// Display Results
var resultsHTML = "
Your Solar Savings Estimate:
";
resultsHTML += "
Net System Cost (after tax credit): $" + netSystemCost.toFixed(2) + "";
resultsHTML += "
Estimated Annual Solar Production (Year 1): " + annualSolarProductionYear1.toFixed(0) + " kWh";
resultsHTML += "
Estimated Annual Electricity Savings (Year 1): $" + annualElectricitySavingsYear1.toFixed(2) + "";
resultsHTML += "
Estimated Payback Period: " + paybackPeriod + (typeof paybackPeriod === 'number' ? " years" : "") + "";
resultsHTML += "
Total Savings Over " + systemLifespan + " Years: $" + totalSavingsOverLifespan.toFixed(2) + "";
resultsDiv.innerHTML = resultsHTML;
}
Understanding Your Solar Savings
Going solar is a significant investment that can lead to substantial long-term savings and environmental benefits. Our Solar Savings Calculator helps you project these financial advantages by considering key factors specific to your situation.
How Solar Panels Save You Money
- Reduced Electricity Bills: The most direct saving comes from generating your own electricity. Instead of buying power from the utility company, your solar panels produce clean energy, significantly lowering or even eliminating your monthly electricity bill.
- Net Metering: In many areas, if your solar panels produce more electricity than you consume, the excess power is sent back to the grid. Your utility company then credits your account for this surplus energy, further reducing your bill or even resulting in a payout.
- Federal Tax Credits: The U.S. federal government offers a significant tax credit (currently 30% through 2032) for homeowners who install solar panels. This directly reduces the upfront cost of your system.
- Increased Home Value: Homes with solar panels often sell faster and for more money than comparable homes without solar.
- Protection Against Rising Electricity Costs: Once your solar system is installed, your "fuel" (sunlight) is free. This insulates you from unpredictable increases in utility rates over the decades.
Key Factors in Your Solar Savings Calculation
The calculator uses several inputs to provide a realistic estimate:
- Average Monthly Electricity Bill: Your current bill helps estimate your annual electricity consumption.
- Current Electricity Cost per kWh: This is crucial for valuing the electricity your solar system will produce. You can usually find this on your utility bill.
- Proposed Solar System Size (kW): The total power output capacity of your solar array. Larger systems generally produce more electricity.
- Estimated Annual kWh per kW of Solar: This factor accounts for your local sunlight conditions and system efficiency. It represents how many kilowatt-hours (kWh) one kilowatt (kW) of solar capacity is expected to produce in a year. This varies significantly by geographic location.
- Total Solar System Cost: The upfront cost of purchasing and installing your solar panels.
- Federal Solar Tax Credit (%): The percentage of your system cost that you can claim as a tax credit.
- Annual Electricity Price Increase (%): Historically, electricity prices tend to rise. This input helps project future savings.
- Annual Solar Panel Degradation (%): Solar panels slowly lose a small amount of efficiency each year. This factor accounts for that gradual decline in production.
- System Lifespan (Years): The expected operational life of your solar panel system, typically 20-30 years.
Interpreting Your Results
- Net System Cost: This is the actual cost you pay after applying the federal tax credit.
- Estimated Annual Solar Production (Year 1): The amount of electricity your system is expected to generate in its first year.
- Estimated Annual Electricity Savings (Year 1): The monetary value of the electricity your system produces in its first year, based on your current electricity cost.
- Estimated Payback Period: The number of years it will take for your cumulative electricity savings to equal your net system cost. A shorter payback period indicates a faster return on investment.
- Total Savings Over System Lifespan: The projected total financial benefit you'll receive from your solar system over its entire operational life, considering electricity inflation and panel degradation.
While this calculator provides a strong estimate, actual savings can vary based on weather patterns, changes in utility rates, specific net metering policies, and system maintenance. For a precise quote and detailed analysis, it's always recommended to consult with local solar installers.