The total number of panels installed on your roof.
Accounts for losses due to wiring, inverter, temperature, soiling. Typical values are 75-90%.
Average hours per day where solar irradiance is around 1000 W/m². Varies by location and season.
Your current rate from the utility company for each kilowatt-hour used.
Estimated Annual Savings
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Understanding Your Solar Panel Savings (kWh)
This calculator estimates the potential annual savings generated by a solar panel system, primarily focusing on the energy produced in kilowatt-hours (kWh) and its equivalent monetary value.
How it Works:
The calculation follows these steps:
Total System Capacity (kWp): First, we determine the total peak power capacity of your solar array by multiplying the wattage of a single panel by the number of panels installed. Total Capacity (Wp) = Panel Wattage (Wp) * Number of Panels. This capacity is then converted to kilowatts (kWp) by dividing by 1000.
Daily Energy Production (kWh): We then estimate the average daily energy production. This considers the total system capacity, the average daily peak sun hours for your location, and the overall system efficiency (which accounts for energy losses). Daily Production (kWh) = Total Capacity (kWp) * Average Daily Peak Sun Hours * (System Efficiency / 100).
Annual Energy Production (kWh): To find the annual production, we multiply the daily production by the number of days in a year. Annual Production (kWh) = Daily Production (kWh) * 365.
Annual Savings ($): Finally, we translate the annual energy production into potential monetary savings by multiplying it by the cost of electricity per kilowatt-hour. Annual Savings ($) = Annual Production (kWh) * Cost of Electricity ($/kWh).
Input Definitions:
Solar Panel Wattage (Wp): The rated power output of a single solar panel under standard test conditions (STC).
Number of Panels: The total count of solar panels in your system.
System Efficiency (%): A crucial factor representing how effectively the system converts sunlight into usable electricity, accounting for real-world losses.
Average Daily Peak Sun Hours: The equivalent number of hours per day when solar irradiance reaches 1000 W/m², a standard measure for comparing solar potential across different locations. This is NOT the same as total daylight hours.
Cost of Electricity ($/kWh): The price you pay your utility provider for each unit of electricity consumed.
Use Cases:
This calculator is useful for:
Homeowners considering a solar installation to estimate potential energy production and cost savings.
Individuals wanting to understand the financial benefits of switching to solar energy.
Comparing the performance of different system sizes and efficiencies.
Disclaimer: This calculator provides an estimate based on the inputs provided. Actual performance may vary due to weather patterns, panel degradation over time, shading, and specific installation factors. It's recommended to consult with a professional solar installer for a precise assessment.
function calculateSolarSavings() {
var panelWattage = parseFloat(document.getElementById("panelWattage").value);
var numberOfPanels = parseInt(document.getElementById("numberOfPanels").value);
var systemEfficiency = parseFloat(document.getElementById("systemEfficiency").value);
var sunHours = parseFloat(document.getElementById("sunHours").value);
var electricityPrice = parseFloat(document.getElementById("electricityPrice").value);
var resultValueElement = document.getElementById("result-value");
var resultUnitElement = document.getElementById("result-unit");
// Input validation
if (isNaN(panelWattage) || panelWattage <= 0 ||
isNaN(numberOfPanels) || numberOfPanels <= 0 ||
isNaN(systemEfficiency) || systemEfficiency 100 ||
isNaN(sunHours) || sunHours < 0 ||
isNaN(electricityPrice) || electricityPrice < 0) {
resultValueElement.innerText = "Invalid";
resultUnitElement.innerText = "Inputs";
return;
}
// Calculations
var totalCapacityWp = panelWattage * numberOfPanels;
var totalCapacityKw = totalCapacityWp / 1000; // Convert Wp to kWp
var dailyProductionKwh = totalCapacityKw * sunHours * (systemEfficiency / 100);
var annualProductionKwh = dailyProductionKwh * 365;
var annualSavings = annualProductionKwh * electricityPrice;
// Display results
resultValueElement.innerText = annualSavings.toFixed(2);
resultUnitElement.innerText = "$";
}