(Average hours of strong sunlight in your location)
15%
Required Solar System Size:
— kW
This is the estimated DC (Direct Current) power capacity needed for your solar panel system.
Understanding Solar Power System Sizing
Determining the right size for your solar power system is crucial for maximizing energy savings and ensuring it meets your household's needs. This calculator helps estimate the required DC (Direct Current) power capacity based on your energy consumption and local solar conditions.
How the Calculator Works:
The core calculation involves several key factors:
Daily Energy Consumption (kWh): This is the total amount of electricity your household uses on an average day, measured in kilowatt-hours (kWh). You can usually find this information on your electricity bills or by monitoring your smart meter.
Peak Sun Hours per Day: This represents the average number of hours per day when sunlight intensity is strong enough to effectively generate power. This varies significantly by geographic location and season. A common range is 3 to 6 hours.
System Losses (%): Solar power systems are not 100% efficient. Losses occur due to factors like panel temperature, shading, inverter efficiency, wiring resistance, and dirt accumulation on the panels. A typical system loss factor is between 10% and 25%.
The Calculation Formula:
The calculator uses the following formula to estimate the required DC system size:
Required System Size (kW) = (Daily Energy Consumption (kWh) / Peak Sun Hours per Day) / (1 – (System Losses (%) / 100))
Let's break this down:
Energy per Hour Needed: We first divide your Daily Energy Consumption by the Peak Sun Hours. This gives us an estimate of how many kW your system needs to produce, on average, during those peak sun hours to meet your daily demand.
Accounting for Losses: The result from step 1 is then divided by a factor that accounts for system inefficiencies (1 – System Losses). For example, if losses are 15%, this factor is 0.85. Dividing by 0.85 effectively increases the required system size to compensate for the energy that will be lost.
Example Calculation:
Let's consider a household with the following:
Daily Energy Consumption: 25 kWh
Peak Sun Hours per Day: 4.5 hours
System Losses: 18%
Step 1: Energy per Hour Needed
25 kWh / 4.5 hours = 5.56 kW (This is the average power needed during peak hours)
Step 2: Adjust for System Losses
1 – (18 / 100) = 0.82
Required System Size (kW)
5.56 kW / 0.82 = 6.78 kW
Therefore, a solar system with a DC capacity of approximately 6.78 kW would be needed for this household under these conditions.
Important Considerations:
This calculator provides an *estimate*. Actual system design should be done by a professional solar installer.
Factors like roof space, shading, orientation, local regulations, and future energy needs should also be considered.
The goal is often to offset a significant portion of your electricity bill, not necessarily 100% of your consumption, depending on your budget and preferences.
var dailyEnergyConsumptionInput = document.getElementById("dailyEnergyConsumption");
var peakSunHoursInput = document.getElementById("peakSunHours");
var systemLossesInput = document.getElementById("systemLosses");
var systemLossesValueSpan = document.getElementById("systemLossesValue");
var resultDiv = document.getElementById("result");
var resultValueDiv = document.getElementById("result-value");
// Update the displayed value for the range slider
systemLossesInput.oninput = function() {
systemLossesValueSpan.innerHTML = this.value + "%";
}
function calculateSolarSize() {
var dailyEnergyConsumption = parseFloat(dailyEnergyConsumptionInput.value);
var peakSunHours = parseFloat(peakSunHoursInput.value);
var systemLosses = parseFloat(systemLossesInput.value);
// Validate inputs
if (isNaN(dailyEnergyConsumption) || dailyEnergyConsumption <= 0) {
alert("Please enter a valid Daily Energy Consumption (must be a positive number).");
return;
}
if (isNaN(peakSunHours) || peakSunHours <= 0) {
alert("Please enter valid Peak Sun Hours (must be a positive number).");
return;
}
if (isNaN(systemLosses) || systemLosses 100) {
alert("Please enter valid System Losses between 0 and 100 percent.");
return;
}
var lossFactor = 1 – (systemLosses / 100);
if (lossFactor === 0) { // Avoid division by zero if losses are 100%
alert("System losses cannot be 100%. Please adjust the value.");
return;
}
// Calculate the required system size in kW
var requiredSizeKW = (dailyEnergyConsumption / peakSunHours) / lossFactor;
// Display the result, rounded to two decimal places
resultValueDiv.innerHTML = requiredSizeKW.toFixed(2) + " kW";
resultDiv.style.display = "block";
}