Energysage Solar Calculator

Solar Savings & System Size Calculator

Your Solar Potential:

function calculateSolar() { var avgMonthlyKwh = parseFloat(document.getElementById('avgMonthlyKwh').value); var peakSunHours = parseFloat(document.getElementById('peakSunHours').value); var costPerWatt = parseFloat(document.getElementById('costPerWatt').value); var federalTaxCredit = parseFloat(document.getElementById('federalTaxCredit').value); var stateIncentives = parseFloat(document.getElementById('stateIncentives').value); var electricityRate = parseFloat(document.getElementById('electricityRate').value); var degradationRate = parseFloat(document.getElementById('degradationRate').value); var inflationRate = parseFloat(document.getElementById('inflationRate').value); // Input validation if (isNaN(avgMonthlyKwh) || avgMonthlyKwh <= 0 || isNaN(peakSunHours) || peakSunHours <= 0 || isNaN(costPerWatt) || costPerWatt <= 0 || isNaN(federalTaxCredit) || federalTaxCredit < 0 || isNaN(stateIncentives) || stateIncentives < 0 || isNaN(electricityRate) || electricityRate <= 0 || isNaN(degradationRate) || degradationRate < 0 || isNaN(inflationRate) || inflationRate < 0) { document.getElementById('solarResults').innerHTML = '

Please enter valid positive numbers for all fields.

'; return; } var systemEfficiencyFactor = 0.8; // Assumed system efficiency (e.g., 80%) // 1. Estimated System Size Needed (kW) var annualKwhConsumption = avgMonthlyKwh * 12; var estimatedSystemSizeKw = annualKwhConsumption / (peakSunHours * 365 * systemEfficiencyFactor); // 2. Estimated Annual kWh Production (based on calculated system size) var annualKwhProduction = estimatedSystemSizeKw * peakSunHours * 365 * systemEfficiencyFactor; // 3. Total System Cost (before incentives) var totalSystemCost = estimatedSystemSizeKw * 1000 * costPerWatt; // 4. Federal Tax Credit Amount var federalTaxCreditAmount = totalSystemCost * (federalTaxCredit / 100); // 5. Net System Cost (after incentives) var netSystemCost = totalSystemCost – federalTaxCreditAmount – stateIncentives; if (netSystemCost < 0) netSystemCost = 0; // System cost cannot be negative // 6. Estimated Annual Savings (Year 1) var year1Savings = annualKwhProduction * electricityRate; // 7. Calculate Payback Period and 25-Year Savings var cumulativeSavings = 0; var paybackPeriod = "N/A"; var currentElectricityRate = electricityRate; var currentAnnualProduction = annualKwhProduction; var total25YearSavings = 0; for (var year = 1; year 1) { currentAnnualProduction *= (1 – degradationRate / 100); } // Adjust electricity rate for inflation if (year > 1) { currentElectricityRate *= (1 + inflationRate / 100); } var yearSavings = currentAnnualProduction * currentElectricityRate; cumulativeSavings += yearSavings; total25YearSavings += yearSavings; if (paybackPeriod === "N/A" && cumulativeSavings >= netSystemCost) { paybackPeriod = year; } } var net25YearSavings = total25YearSavings – netSystemCost; if (net25YearSavings < 0) net25YearSavings = 0; // Savings cannot be negative if system cost is not covered // Display Results document.getElementById('resultSystemSize').innerHTML = 'Estimated System Size Needed: ' + estimatedSystemSizeKw.toFixed(2) + ' kW'; document.getElementById('resultAnnualProduction').innerHTML = 'Estimated Annual kWh Production: ' + annualKwhProduction.toFixed(0) + ' kWh'; document.getElementById('resultTotalCost').innerHTML = 'Total System Cost (before incentives): $' + totalSystemCost.toFixed(2); document.getElementById('resultNetCost').innerHTML = 'Net System Cost (after incentives): $' + netSystemCost.toFixed(2); document.getElementById('resultYear1Savings').innerHTML = 'Estimated Annual Savings (Year 1): $' + year1Savings.toFixed(2); document.getElementById('resultPaybackPeriod').innerHTML = 'Estimated Payback Period: ' + (paybackPeriod === "N/A" ? "More than 25 years" : paybackPeriod + ' years'); document.getElementById('resultTwentyFiveYearSavings').innerHTML = 'Estimated 25-Year Net Savings: $' + net25YearSavings.toFixed(2); }

Understanding Your Solar Potential with the EnergySage Solar Calculator

Going solar is a significant investment that can lead to substantial long-term savings and environmental benefits. Our Solar Savings & System Size Calculator, inspired by tools like EnergySage, helps you estimate the ideal solar panel system size for your home and project your potential financial returns over time. This tool empowers you to make informed decisions about your solar journey.

How Solar Power Works for Your Home

Solar panels, typically installed on your roof, capture sunlight and convert it into direct current (DC) electricity. An inverter then converts this DC electricity into alternating current (AC) electricity, which is the type of power used by your home appliances. Any excess electricity your panels produce can often be sent back to the grid, potentially earning you credits through a process called net metering, depending on your local utility policies.

Key Factors Influencing Your Solar Savings

Several variables determine how much electricity your solar system will generate and how much money you'll save. Our calculator takes these crucial factors into account:

• Average Monthly Electricity Consumption (kWh): This is the most critical input, representing how much electricity your household uses. A higher consumption generally means a larger system is needed to offset your bill.
• Average Daily Peak Sun Hours: This refers to the average number of hours per day your solar panels receive direct, effective sunlight. It varies significantly by geographic location and time of year. More peak sun hours mean more electricity generation.
• Average System Cost per Watt ($/W): This is the industry benchmark for solar system pricing. It includes panels, inverters, mounting hardware, labor, and permitting. Prices vary by region, installer, and system quality.
• Federal Solar Tax Credit (%): The Investment Tax Credit (ITC) is a significant federal incentive that allows homeowners to deduct a percentage of the cost of installing a solar energy system from their federal taxes.
• State/Local Incentives (flat $): Many states and local municipalities offer additional rebates, tax credits, or performance-based incentives to encourage solar adoption.
• Current Electricity Rate ($/kWh): Your current cost of electricity directly impacts your savings. The higher your rate, the more you save by generating your own power.
• Annual System Degradation Rate (%): Solar panels gradually become less efficient over time. This rate, typically around 0.5% per year, accounts for this natural decline in performance.
• Annual Electricity Price Inflation Rate (%): Electricity prices from utilities tend to increase over time. Factoring in this inflation helps project future savings more accurately.

How to Use the Calculator

1. Enter Your Monthly kWh Consumption: Find this on your recent electricity bills.
2. Input Peak Sun Hours: You can find average peak sun hours for your specific location online (e.g., from NREL's PVWatts calculator or local solar resources).
3. Provide Cost per Watt: Research average solar installation costs in your area. EnergySage provides good benchmarks.
4. Add Incentives: Enter the current federal tax credit percentage and any specific state or local rebates you know of.
5. Specify Electricity Rate: Your current electricity bill will show your average rate per kWh.
6. Adjust Degradation & Inflation: Use the default values or adjust them based on your research or specific panel warranty.
7. Click "Calculate Solar Savings": The calculator will instantly provide estimates for your system size, costs, and long-term savings.

Interpreting Your Results

• Estimated System Size Needed (kW): This is the recommended size of your solar array to offset your current electricity usage.
• Estimated Annual kWh Production: The amount of electricity your system is expected to generate in a year.
• Total System Cost (before incentives): The full price of the system before any tax credits or rebates.
• Net System Cost (after incentives): Your out-of-pocket cost after applying all eligible incentives.
• Estimated Annual Savings (Year 1): How much you can expect to save on your electricity bill in the first year.
• Estimated Payback Period: The number of years it will take for your cumulative savings to equal your net system cost.
• Estimated 25-Year Net Savings: The total financial benefit you can expect over the typical lifespan of a solar panel system, accounting for degradation and electricity price increases.

Remember, this calculator provides estimates. For precise figures and a personalized quote, it's always best to consult with multiple qualified local solar installers. They can assess your specific roof, energy needs, and local regulations to provide an accurate proposal.