Solar Panel Sizing & Savings Calculator
(e.g., 30 kWh for an average household)
(Varies by location and season, e.g., 4-5 hours)
(Typical panel output, e.g., 350W – 450W)
(Accounts for real-world losses like temperature, dust, wiring, inverter efficiency. Typically 75-85%)
(Your average cost per kilowatt-hour)
(Average cost including panels, inverter, installation, etc.)
Your Solar Potential Results:
Please enter valid positive numbers for all fields.
'; return; } var deratingFactorDecimal = deratingFactor / 100; // Energy produced per panel per day (kWh) var energyProducedPerPanelPerDay = (panelWattage * peakSunHours * deratingFactorDecimal) / 1000; // Convert Wh to kWh if (energyProducedPerPanelPerDay === 0) { resultDiv.innerHTML = 'Cannot calculate: Panel production is zero. Check peak sun hours or panel wattage.
'; return; } // Number of panels required var numPanelsRequired = Math.ceil(dailyKwhConsumption / energyProducedPerPanelPerDay); // Total system wattage (W) var totalSystemWattage = numPanelsRequired * panelWattage; // Estimated total installation cost ($) var totalInstallationCost = totalSystemWattage * costPerWatt; // Estimated daily savings ($) var dailySavings = dailyKwhConsumption * electricityRate; // Estimated annual savings ($) var annualSavings = dailySavings * 365; // Estimated payback period (Years) var paybackPeriod = (annualSavings > 0) ? totalInstallationCost / annualSavings : Infinity; numPanelsElem.innerHTML = 'Estimated Number of Panels Needed: ' + numPanelsRequired + ' panels'; totalSystemWattageElem.innerHTML = 'Total System Wattage: ' + (totalSystemWattage / 1000).toFixed(2) + ' kW'; totalInstallationCostElem.innerHTML = 'Estimated Total Installation Cost: $' + totalInstallationCost.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }); dailySavingsElem.innerHTML = 'Estimated Daily Electricity Savings: $' + dailySavings.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }); annualSavingsElem.innerHTML = 'Estimated Annual Electricity Savings: $' + annualSavings.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }); paybackPeriodElem.innerHTML = 'Estimated Payback Period: ' + (paybackPeriod === Infinity ? 'N/A (No savings)' : paybackPeriod.toFixed(1) + ' years'); }Understanding Your Solar Potential
Going solar is a significant investment that can lead to substantial long-term savings and environmental benefits. This calculator helps you estimate the number of solar panels you might need, the potential cost, and the financial returns based on your specific energy consumption and local conditions.
How Solar Panels Work
Solar panels, also known as photovoltaic (PV) panels, convert sunlight into direct current (DC) electricity. An inverter then converts this DC electricity into alternating current (AC) electricity, which is what your home appliances use. Any excess electricity produced can often be fed back into the grid, potentially earning you credits through net metering programs.
Key Factors in Your Solar Calculation:
- Average Daily Energy Consumption (kWh): This is the most crucial input, representing how much electricity your household uses daily. You can usually find this on your electricity bills. The goal of a solar system is often to offset a significant portion, if not all, of this consumption.
- Average Peak Sun Hours per Day (hours): This refers to the number of hours per day when the intensity of sunlight is equivalent to 1,000 watts per square meter. It's a measure of solar insolation and varies significantly by geographic location, season, and local weather patterns. More peak sun hours mean more electricity generation.
- Individual Solar Panel Wattage (W): This is the power output rating of a single solar panel under standard test conditions. Common residential panels range from 350W to 450W. Higher wattage panels can produce more electricity with fewer physical panels.
- System Derating Factor (%): Solar panels rarely perform at their absolute peak efficiency in real-world conditions. This factor accounts for various losses due to temperature, dust, shading, wiring resistance, and inverter efficiency. A typical derating factor is between 75% and 85%.
- Current Electricity Rate ($/kWh): Your current cost per unit of electricity directly impacts your potential savings. The higher your rate, the more you stand to save by generating your own power.
- Estimated Installation Cost per Watt ($/W): This is an average cost that includes the panels, inverter, mounting hardware, labor, permits, and other associated expenses. This figure can vary widely based on location, system size, installer, and specific equipment chosen.
Interpreting Your Results:
The calculator provides estimates for:
- Estimated Number of Panels Needed: The approximate quantity of panels required to meet your daily energy consumption.
- Total System Wattage: The combined power output of all the estimated panels, typically expressed in kilowatts (kW).
- Estimated Total Installation Cost: A rough estimate of the upfront investment for your solar system. Remember to factor in potential incentives like federal tax credits or local rebates, which can significantly reduce this cost.
- Estimated Daily/Annual Electricity Savings: How much money you could save on your electricity bill by generating your own power.
- Estimated Payback Period: The approximate time it will take for your accumulated electricity savings to equal the initial cost of your solar system.
This calculator provides a useful starting point for understanding your solar potential. For an accurate assessment and detailed quote, it's always recommended to consult with multiple qualified local solar installers who can evaluate your specific property, energy needs, and available incentives.