Solar Calculator

Solar Panel Output & Savings Calculator

Use this calculator to estimate the electricity production and potential savings from a solar panel system based on your specific inputs. This tool helps you understand the energy output and financial benefits of going solar.

hours

Enter the average number of peak sun hours your location receives per day. This is not just daylight hours, but hours where the sun's intensity is at its peak (around 1000 W/m²).

Watts

Specify the wattage of a single solar panel in your system (e.g., 350W, 400W).

panels

Enter the total number of solar panels you plan to install.

%

Account for efficiency losses due to factors like temperature, wiring, dust, inverter efficiency, and shading. A typical range is 15-25%.

$/kWh

Input your average electricity cost per kilowatt-hour (kWh) from your utility bill.

Estimated Results:

Please enter valid numbers and click "Calculate Solar Output" to see your estimates.

function calculateSolarOutput() { var peakSunHours = parseFloat(document.getElementById('peakSunHours').value); var panelWattage = parseFloat(document.getElementById('panelWattage').value); var numPanels = parseFloat(document.getElementById('numPanels').value); var systemEfficiencyLoss = parseFloat(document.getElementById('systemEfficiency').value); var electricityCost = parseFloat(document.getElementById('electricityCost').value); var resultDiv = document.getElementById('result'); if (isNaN(peakSunHours) || isNaN(panelWattage) || isNaN(numPanels) || isNaN(systemEfficiencyLoss) || isNaN(electricityCost) || peakSunHours <= 0 || panelWattage <= 0 || numPanels <= 0 || systemEfficiencyLoss 100 || electricityCost < 0) { resultDiv.innerHTML = 'Please enter valid positive numbers for all fields. System Efficiency Loss must be between 0 and 100.'; return; } // Convert efficiency loss percentage to a multiplier (e.g., 15% loss = 0.85 efficiency) var efficiencyMultiplier = (100 – systemEfficiencyLoss) / 100; // 1. Total System Wattage (DC) var totalSystemWattage = panelWattage * numPanels; // Watts // 2. Daily kWh Production (DC) var dailyWhProductionDC = totalSystemWattage * peakSunHours; // Watt-hours var dailyKwhProductionDC = dailyWhProductionDC / 1000; // kWh // 3. Daily kWh Production (AC, after efficiency loss) var dailyKwhProductionAC = dailyKwhProductionDC * efficiencyMultiplier; // kWh // 4. Monthly kWh Production (using average 30.44 days/month) var monthlyKwhProduction = dailyKwhProductionAC * 30.44; // kWh // 5. Annual kWh Production (using 365 days/year) var annualKwhProduction = dailyKwhProductionAC * 365; // kWh // 6. Monthly Savings var monthlySavings = monthlyKwhProduction * electricityCost; // $ // 7. Annual Savings var annualSavings = annualKwhProduction * electricityCost; // $ resultDiv.innerHTML = 'Estimated Daily kWh Production: ' + dailyKwhProductionAC.toFixed(2) + ' kWh' + 'Estimated Monthly kWh Production: ' + monthlyKwhProduction.toFixed(2) + ' kWh' + 'Estimated Annual kWh Production: ' + annualKwhProduction.toFixed(2) + ' kWh' + 'Estimated Monthly Electricity Bill Savings: $' + monthlySavings.toFixed(2) + " + 'Estimated Annual Electricity Bill Savings: $' + annualSavings.toFixed(2) + "; } .calculator-container { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; padding: 25px; border-radius: 10px; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1); max-width: 700px; margin: 20px auto; border: 1px solid #e0e0e0; } .calculator-container h2 { color: #2c3e50; text-align: center; margin-bottom: 20px; font-size: 1.8em; } .calculator-container p { color: #555; line-height: 1.6; margin-bottom: 15px; } .calc-input-group { margin-bottom: 18px; display: flex; flex-wrap: wrap; align-items: center; border: 1px solid #ddd; padding: 12px; border-radius: 8px; background-color: #fff; } .calc-input-group label { flex: 1 1 100%; color: #34495e; margin-bottom: 8px; font-weight: bold; font-size: 1.05em; } .calc-input-group input[type="number"] { flex: 2 1 60%; padding: 10px 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 1em; box-sizing: border-box; margin-right: 10px; max-width: 200px; /* Limit input width */ } .calc-input-group .input-unit { flex: 0 0 auto; padding: 10px 0; color: #777; font-size: 0.95em; margin-left: -5px; /* Adjust unit positioning */ } .calc-input-group .input-help { flex: 1 1 100%; font-size: 0.85em; color: #7f8c8d; margin-top: 8px; padding-top: 5px; border-top: 1px dashed #eee; } .calculator-container button { display: block; width: 100%; padding: 12px 20px; background-color: #28a745; color: white; border: none; border-radius: 5px; font-size: 1.1em; cursor: pointer; transition: background-color 0.3s ease, transform 0.2s ease; margin-top: 25px; font-weight: bold; } .calculator-container button:hover { background-color: #218838; transform: translateY(-2px); } .calculator-container button:active { background-color: #1e7e34; transform: translateY(0); } .calc-results { background-color: #eaf7ed; border: 1px solid #d4edda; border-radius: 8px; padding: 20px; margin-top: 30px; box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.05); } .calc-results h3 { color: #28a745; margin-top: 0; margin-bottom: 15px; font-size: 1.5em; text-align: center; } .calc-results p { font-size: 1.1em; color: #333; margin-bottom: 10px; display: flex; justify-content: space-between; align-items: center; padding-bottom: 5px; border-bottom: 1px dotted #c3e6cb; } .calc-results p:last-child { margin-bottom: 0; border-bottom: none; font-weight: bold; color: #1e7e34; } .calc-results p strong { color: #2c3e50; flex-basis: 70%; text-align: left; } .calc-results p span { flex-basis: 30%; text-align: right; } @media (max-width: 600px) { .calc-input-group input[type="number"] { flex: 1 1 50%; margin-right: 5px; } .calc-input-group .input-unit { flex: 0 0 auto; margin-left: 0; } .calc-results p { flex-direction: column; align-items: flex-start; } .calc-results p strong, .calc-results p span { flex-basis: 100%; text-align: left; } .calc-results p span { margin-top: 5px; font-size: 0.9em; color: #555; } }

Understanding Your Solar Panel Output & Savings

Going solar is a significant investment, and understanding its potential energy output and financial benefits is crucial. Our Solar Panel Output & Savings Calculator helps you estimate how much electricity your system could generate and the money you might save on your utility bills.

How Solar Panel Output is Calculated

The electricity generated by a solar panel system depends on several key factors:

  • Average Daily Peak Sun Hours: This is not simply the number of hours the sun is visible, but rather the equivalent hours per day when solar irradiance averages 1,000 watts per square meter. Factors like geographic location, season, and local weather patterns heavily influence this. For example, a sunny state like Arizona might have 5-6 peak sun hours, while a cloudier region might have 3-4.
  • Individual Solar Panel Wattage: This refers to the power rating of a single solar panel under standard test conditions (STC). Modern residential panels typically range from 300W to 450W. Higher wattage panels can produce more electricity per panel.
  • Number of Solar Panels: The more panels you install, the larger your system's total capacity, and thus, the more electricity it can generate.
  • System Efficiency Loss: No solar system operates at 100% efficiency. Various factors contribute to energy loss, including:
    • Temperature: Panels become less efficient as they get hotter.
    • Inverter Efficiency: Inverters convert DC electricity from panels to AC electricity for your home, and this process involves some loss (typically 3-5%).
    • Wiring Losses: Resistance in electrical wiring causes minor energy loss.
    • Dust and Shading: Accumulation of dust, dirt, or partial shading from trees or chimneys can reduce output.
    • Panel Degradation: Solar panels slowly lose efficiency over their lifespan (typically 0.5% to 1% per year).
    A typical system efficiency loss factor ranges from 15% to 25%.
  • Average Electricity Cost: Your local electricity rate (per kilowatt-hour, kWh) directly impacts your potential savings. Higher electricity costs mean greater financial benefits from generating your own power.

Understanding the Calculator's Results

The calculator provides estimates for:

  • Estimated Daily, Monthly, and Annual kWh Production: This shows you the amount of clean electricity your solar system is expected to generate over different periods. This figure is crucial for understanding how much of your home's electricity needs could be met by solar.
  • Estimated Monthly and Annual Electricity Bill Savings: By multiplying your estimated kWh production by your average electricity cost, the calculator projects the financial savings you could realize by reducing your reliance on grid electricity.

Example Scenario:

Let's consider a homeowner in a moderately sunny region:

  • Average Daily Peak Sun Hours: 4.5 hours
  • Individual Solar Panel Wattage: 400 Watts
  • Number of Solar Panels: 15 panels
  • System Efficiency Loss: 15%
  • Average Electricity Cost: $0.18/kWh

Using these inputs, the calculator would estimate:

  • Total System Wattage: 15 panels * 400W/panel = 6000 Watts (6 kW)
  • Daily kWh Production (DC): 6000W * 4.5 hours / 1000 = 27 kWh
  • Daily kWh Production (AC, after 15% loss): 27 kWh * (1 – 0.15) = 22.95 kWh
  • Monthly kWh Production: 22.95 kWh/day * 30.44 days/month ≈ 698.6 kWh
  • Annual kWh Production: 22.95 kWh/day * 365 days/year ≈ 8376.75 kWh
  • Monthly Savings: 698.6 kWh * $0.18/kWh ≈ $125.75
  • Annual Savings: 8376.75 kWh * $0.18/kWh ≈ $1507.82

These estimates provide a solid foundation for evaluating the economic viability of a solar installation for your home.

Important Considerations:

While this calculator provides valuable estimates, actual results can vary. Factors like seasonal changes in sunlight, specific weather events, panel degradation over time, and changes in electricity rates will influence your system's performance and savings. For precise figures and a tailored assessment, it's always recommended to consult with a professional solar installer who can conduct a detailed site analysis.

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