Estimate the potential savings and system size for your solar investment.
Estimated Annual Savings:
$0.00
Estimated System Size:
0 kW
Total System Cost:
$0.00
Understanding Your Solar Power System Calculation
Investing in a solar power system is a significant decision, impacting both your environmental footprint and your finances. This calculator provides an estimate of key metrics to help you understand the potential benefits of going solar. By inputting specific details about your energy consumption and local conditions, you can gain valuable insights into system sizing, potential cost savings, and the overall financial viability of a solar installation.
How the Calculation Works:
The calculator uses several key inputs to estimate your system's performance and financial return:
Average Daily Energy Consumption (kWh): This is the amount of electricity your household or business typically uses each day, measured in kilowatt-hours. Knowing this is fundamental to sizing a system that can meet your needs.
Peak Sun Hours per Day (Average): This refers to the average number of hours per day that your location receives direct sunlight equivalent to 1000 watts per square meter. It's a crucial factor in determining how much energy your panels can generate.
System Efficiency (%): Solar panel systems aren't 100% efficient. This input accounts for losses due to factors like temperature, shading, inverter efficiency, and wiring. A typical range is 75% to 90%.
System Cost per Watt ($): This is the total installed cost of the solar system divided by its rated capacity in watts. For example, a 5000-watt (5 kW) system costing $15,000 would have a cost per watt of $3.00 ($15,000 / 5000).
Electricity Cost per kWh ($): This is the rate you currently pay your utility company for electricity. The higher this rate, the greater your potential savings from solar.
Net Metering/Incentive Rate (Multiplier): Many regions offer net metering, where you receive credit for excess energy sent back to the grid. This multiplier (often expressed as a percentage of your retail electricity rate) reflects the value of that exported energy. A value of 1 means full retail credit, while 0.8 means 80% credit.
Key Formulas Used:
Estimated Daily Energy Generation (kWh): Daily Generation = (Peak Sun Hours * System Size in kW * System Efficiency) / 1000 (Note: The calculator first determines the required system size to meet consumption and then uses this to calculate generation.)
Required System Size (kW): Required System Size (kW) = Average Daily Energy Consumption (kWh) / (Peak Sun Hours * System Efficiency / 100) This calculates the minimum system size needed to cover your daily consumption, assuming ideal conditions.
Estimated Annual Energy Production (kWh): Annual Production = Daily Generation * 365
Estimated Annual Electricity Savings ($): Annual Savings = (Annual Production * Electricity Cost per kWh) * Incentive Rate This estimates the value of the electricity your system generates and is credited for.
Total System Cost ($): Total Cost = Required System Size (kW) * 1000 * System Cost per Watt ($) This is the estimated upfront cost to purchase and install the system.
Use Cases and Considerations:
This calculator is a valuable tool for:
Homeowners: Evaluating the feasibility and potential ROI of installing solar panels on their residence.
Business Owners: Assessing the financial benefits of a commercial solar installation.
Policy Makers and Researchers: Understanding the impact of different solar incentives and efficiencies.
Important Note: This calculator provides an *estimate*. Actual performance can vary based on specific roof orientation, shading, panel degradation over time, local weather patterns, and utility-specific rate structures and net metering policies. Always consult with a professional solar installer for a detailed site assessment and accurate quotation.
function calculateSolarSystem() {
var avgDailyEnergy = parseFloat(document.getElementById("avgDailyEnergy").value);
var peakSunHours = parseFloat(document.getElementById("peakSunHours").value);
var systemEfficiency = parseFloat(document.getElementById("systemEfficiency").value);
var systemCostPerWatt = parseFloat(document.getElementById("systemCostPerWatt").value);
var electricityCostPerKwh = parseFloat(document.getElementById("electricityCostPerKwh").value);
var incentiveRate = parseFloat(document.getElementById("incentiveRate").value);
var resultValueDiv = document.getElementById("result-value");
var resultSizeDiv = document.getElementById("result-size");
var resultCostDiv = document.getElementById("result-cost");
// Validate inputs
if (isNaN(avgDailyEnergy) || avgDailyEnergy <= 0 ||
isNaN(peakSunHours) || peakSunHours <= 0 ||
isNaN(systemEfficiency) || systemEfficiency 100 ||
isNaN(systemCostPerWatt) || systemCostPerWatt <= 0 ||
isNaN(electricityCostPerKwh) || electricityCostPerKwh < 0 ||
isNaN(incentiveRate) || incentiveRate 1) {
resultValueDiv.textContent = "Invalid input. Please check values.";
resultSizeDiv.textContent = "-";
resultCostDiv.textContent = "-";
return;
}
// Calculate required system size in kW
var requiredSystemSizeKW = avgDailyEnergy / (peakSunHours * (systemEfficiency / 100));
// Calculate estimated annual energy production in kWh
var estimatedDailyGeneration = requiredSystemSizeKW * peakSunHours * (systemEfficiency / 100);
var estimatedAnnualProduction = estimatedDailyGeneration * 365;
// Calculate estimated annual savings in $
var estimatedAnnualSavings = estimatedAnnualProduction * electricityCostPerKwh * incentiveRate;
// Calculate total system cost in $
var totalSystemCost = requiredSystemSizeKW * 1000 * systemCostPerWatt; // Convert kW to Watts
// Format and display results
resultValueDiv.textContent = "$" + estimatedAnnualSavings.toFixed(2);
resultSizeDiv.textContent = requiredSystemSizeKW.toFixed(2) + " kW";
resultCostDiv.textContent = "$" + totalSystemCost.toFixed(2);
}