Your estimated annual savings will be displayed here.
Understanding Your Solar Savings
Installing solar panels is a significant investment, but it can lead to substantial long-term savings on your electricity bills. This calculator helps you estimate your potential annual savings and the payback period for your solar investment.
How it Works: The Math Behind the Savings
The calculator uses several key inputs to estimate your financial benefit from solar panels:
Annual Electricity Usage (kWh): This is the total amount of electricity your household consumes in a year, typically found on your utility bills.
Cost Per kWh ($): This is the rate you pay your utility company for each kilowatt-hour of electricity.
Solar System Size (kW): This refers to the rated capacity of your solar panel system. A larger system can generate more electricity.
Annual Production Factor (kWh/kW): This factor estimates how much energy (in kWh) a 1kW solar system will produce annually in your specific location. It's influenced by sunlight hours, panel orientation, and efficiency. A common range is 1000-1600 kWh/kW.
Total System Cost ($): The upfront cost of purchasing and installing the solar panel system.
Total Incentives & Rebates ($): This includes any government tax credits, local rebates, or other financial incentives that reduce the net cost of the system.
The calculation proceeds as follows:
Estimated Annual Solar Production: This is calculated by multiplying the system size (kW) by the annual production factor (kWh/kW).
Formula: System Size (kW) * Annual Production Factor (kWh/kW) = Annual Production (kWh)
Estimated Annual Electricity Bill Savings: This is determined by multiplying the estimated annual solar production by the cost per kWh. This represents the value of the electricity your solar panels will generate, offsetting what you would otherwise buy from the grid.
Formula: Annual Production (kWh) * Cost Per kWh ($) = Annual Savings ($)
Net System Cost: The total cost of the system minus any incentives and rebates.
Formula: Total System Cost ($) – Total Incentives & Rebates ($) = Net System Cost ($)
Simple Payback Period (Years): This estimates how long it will take for the accumulated annual savings to equal the net cost of the system.
Formula: Net System Cost ($) / Annual Savings ($) = Payback Period (Years)
Use Cases and Considerations:
Financial Planning: Helps homeowners understand the potential return on investment for solar energy.
Budgeting: Assists in estimating the upfront costs after factoring in incentives.
Decision Making: Provides data to compare solar with other energy sources or home improvement projects.
Factors Not Included: This calculator provides a simplified estimate. Actual savings can be affected by factors like degradation of panel efficiency over time, changes in electricity rates, net metering policies, maintenance costs, and potential home resale value increase.
Use this calculator as a starting point for your solar energy journey. Always consult with solar professionals for a personalized assessment and quote.
function calculateSolarSavings() {
var annualElectricityUsage = parseFloat(document.getElementById("annualElectricityUsage").value);
var costPerKwh = parseFloat(document.getElementById("costPerKwh").value);
var systemSizeKw = parseFloat(document.getElementById("systemSizeKw").value);
var annualProductionFactor = parseFloat(document.getElementById("annualProductionFactor").value);
var systemCost = parseFloat(document.getElementById("systemCost").value);
var incentives = parseFloat(document.getElementById("incentives").value);
var resultDiv = document.getElementById("result");
// Input validation
if (isNaN(annualElectricityUsage) || annualElectricityUsage < 0) {
resultDiv.innerHTML = "Please enter a valid Annual Electricity Usage.";
return;
}
if (isNaN(costPerKwh) || costPerKwh <= 0) {
resultDiv.innerHTML = "Please enter a valid Cost Per kWh (must be greater than 0).";
return;
}
if (isNaN(systemSizeKw) || systemSizeKw <= 0) {
resultDiv.innerHTML = "Please enter a valid Solar System Size (must be greater than 0).";
return;
}
if (isNaN(annualProductionFactor) || annualProductionFactor <= 0) {
resultDiv.innerHTML = "Please enter a valid Annual Production Factor (must be greater than 0).";
return;
}
if (isNaN(systemCost) || systemCost < 0) {
resultDiv.innerHTML = "Please enter a valid Total System Cost.";
return;
}
if (isNaN(incentives) || incentives 0) {
paybackPeriod = netSystemCost / annualSavings;
} else {
paybackPeriod = Infinity; // Avoid division by zero if savings are 0
}
resultDiv.innerHTML = "Estimated Annual Savings: $" + annualSavings.toFixed(2) + "" +
"Estimated Net System Cost: $" + netSystemCost.toFixed(2) + "" +
"Estimated Simple Payback Period: " + (paybackPeriod === Infinity ? "N/A (Insufficient Savings)" : paybackPeriod.toFixed(1) + " years") + "";
}