Estimate your potential annual solar energy production and savings.
Average daily hours of direct sunlight equivalent to peak intensity.
85%
Estimated Annual Savings:
$0.00
Understanding Your Solar Power Potential
Installing a solar power system is a significant investment that can lead to substantial long-term savings and contribute to a cleaner environment. This calculator helps you estimate the potential energy production and the resulting financial benefits of a solar photovoltaic (PV) system.
Key Metrics Explained:
System Size (kW): This refers to the direct current (DC) nameplate capacity of your solar panel array. For example, a 5 kW system is composed of panels that, under ideal test conditions, can produce 5 kilowatts of power.
Peak Sun Hours per Day: This is a crucial factor for solar production. It's not the total number of daylight hours, but rather the equivalent number of hours per day when solar irradiance averages 1,000 watts per square meter (W/m²). Regions with higher peak sun hours generally yield more energy from the same system size.
System Efficiency (%): Solar panels and the entire system (including inverters, wiring, and installation factors) are not 100% efficient. This metric accounts for energy losses due to factors like temperature, dust, shading, and component performance. A typical modern system might have an effective efficiency between 75% and 85%.
Electricity Cost per kWh ($): This is the rate you currently pay your utility company for each kilowatt-hour of electricity consumed. The higher this rate, the greater your potential savings from generating your own solar power.
Annual Maintenance Cost ($): Solar systems require some level of maintenance, such as cleaning, occasional inspections, and potential inverter replacement over their lifespan. This input helps factor in those ongoing costs.
How the Calculation Works:
The calculator uses the following formulas to estimate your solar power system's performance and savings:
Daily Energy Production (kWh): Daily Production = System Size (kW) × Peak Sun Hours × System Efficiency (as decimal) For example, a 5 kW system with 4.5 peak sun hours and 85% efficiency produces:
5 kW × 4.5 hours × 0.85 = 19.125 kWh per day
Annual Energy Production (kWh): Annual Production = Daily Production × 365 days Continuing the example:
19.125 kWh/day × 365 days = 6,981.875 kWh per year
Gross Annual Savings ($): This is the value of the electricity your system generates, based on your current electricity rate.
Gross Savings = Annual Production × Electricity Cost per kWh With an electricity cost of $0.15/kWh:
6,981.875 kWh × $0.15/kWh = $1,047.28 (approximately)
Net Annual Savings ($): This subtracts the estimated annual maintenance costs to give a more realistic savings figure.
Net Savings = Gross Savings - Annual Maintenance Cost If maintenance is $50/year:
$1,047.28 - $50 = $997.28
Use Cases and Considerations:
This calculator provides a valuable estimate for homeowners and businesses considering solar installation. It helps in:
Understanding the potential return on investment (ROI) for solar panels.
Comparing different system sizes and locations based on average sunlight.
Justifying the upfront cost of solar installation by projecting long-term savings.
Budgeting for ongoing maintenance costs.
Important Note: This is an estimation tool. Actual energy production and savings can vary based on specific site conditions, panel degradation over time, local weather patterns, utility rate changes, and shading. Professional solar installers can provide a more precise assessment.
function calculateSolarPower() {
// Get input values
var systemSize = parseFloat(document.getElementById("systemSize").value);
var peakSunHours = parseFloat(document.getElementById("peakSunHours").value);
// Get efficiency value from the hidden input, assuming it's updated by the slider
var systemEfficiencyPercent = parseFloat(document.getElementById("systemEfficiency").value);
var electricityRate = parseFloat(document.getElementById("electricityRate").value);
var maintenanceCost = parseFloat(document.getElementById("maintenanceCost").value);
// Input validation
var inputsValid = true;
if (isNaN(systemSize) || systemSize <= 0) {
alert("Please enter a valid System Size (kW).");
inputsValid = false;
}
if (isNaN(peakSunHours) || peakSunHours <= 0) {
alert("Please enter valid Peak Sun Hours per Day.");
inputsValid = false;
}
if (isNaN(systemEfficiencyPercent) || systemEfficiencyPercent 100) {
alert("Please enter a valid System Efficiency between 0% and 100%.");
inputsValid = false;
}
if (isNaN(electricityRate) || electricityRate < 0) {
alert("Please enter a valid Electricity Cost per kWh.");
inputsValid = false;
}
if (isNaN(maintenanceCost) || maintenanceCost < 0) {
alert("Please enter a valid Annual Maintenance Cost.");
inputsValid = false;
}
if (!inputsValid) {
document.getElementById("result-value").innerText = "Invalid Input";
document.getElementById("additional-info").innerText = "";
return;
}
// Convert efficiency percentage to decimal
var systemEfficiencyDecimal = systemEfficiencyPercent / 100;
// Calculations
var dailyProduction = systemSize * peakSunHours * systemEfficiencyDecimal;
var annualProduction = dailyProduction * 365;
var grossAnnualSavings = annualProduction * electricityRate;
var netAnnualSavings = grossAnnualSavings – maintenanceCost;
// Ensure net savings is not negative if maintenance cost is high
if (netAnnualSavings < 0) {
netAnnualSavings = 0;
}
// Format results
var formattedNetSavings = netAnnualSavings.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
var formattedAnnualProduction = annualProduction.toLocaleString(undefined, { minimumFractionDigits: 0, maximumFractionDigits: 0 });
// Display results
document.getElementById("result-value").innerText = "$" + formattedNetSavings;
document.getElementById("additional-info").innerText =
"Estimated Annual Production: " + formattedAnnualProduction + " kWh";
}
// Update the hidden input value when the slider moves
document.getElementById("systemEfficiency").addEventListener("input", function() {
document.getElementById("systemEfficiency").value = this.value;
document.getElementById("systemEfficiencyValue").innerText = this.value + '%';
});
// Initial calculation on page load if values are present
document.addEventListener('DOMContentLoaded', function() {
calculateSolarPower();
});