Solar Panel System Calculator
Use this calculator to estimate the size and cost of a solar panel system needed to meet your energy demands, based on your average daily energy consumption and local sunlight conditions.
Enter your average daily electricity usage in kilowatt-hours (kWh). You can usually find this on your electricity bill.
This represents the equivalent hours per day when solar irradiance averages 1,000 watts per square meter. This varies by location and time of year. A common range is 3-6 hours.
The power output of a single solar panel. Common panels range from 300W to 500W.
Accounts for energy losses due to wiring, inverter inefficiency, temperature, dust, and shading. A typical range is 10-25%.
The percentage of your daily energy consumption you wish to cover with solar power.
The average cost to install solar per watt, including panels, inverter, installation, etc. This varies significantly by region and system size.
Your current electricity rate per kilowatt-hour. Found on your utility bill.
Understanding Solar Power and Your Energy Needs
Going solar is a significant step towards energy independence and reducing your carbon footprint. This calculator helps you get a preliminary estimate of what a solar system might look like for your home or business.
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 Solar System Sizing
- Average Daily Energy Consumption (kWh): This is the most critical input. Your electricity bill will show your monthly or annual consumption, which you can divide to get a daily average. The more energy you use, the larger the solar system you'll need.
- Average Daily Peak Sun Hours: This isn't just the number of hours the sun is out, but the equivalent hours of direct, intense sunlight. Factors like geographic location, season, weather patterns, and roof orientation significantly impact this. Online resources or local solar installers can provide more precise peak sun hour data for your area.
- Individual Solar Panel Wattage: Panels come in various power outputs. Higher wattage panels mean fewer panels are needed for the same total system size, potentially saving roof space.
- System Loss Factor: No system is 100% efficient. Losses occur due to temperature, dust, shading, wiring resistance, and the efficiency of the inverter. A typical system loss factor is between 10-25%.
- Desired Energy Offset: You might not want to cover 100% of your energy needs with solar, especially if you have high consumption or limited roof space. This allows you to plan for a partial offset.
Interpreting Your Results
The calculator provides several key outputs:
- Daily Energy Needed from Solar: This is your target daily production based on your consumption and desired offset.
- Total Solar System Wattage Required: The total power capacity (in watts) your solar array needs to generate to meet your daily energy target, accounting for system losses and peak sun hours.
- Number of Solar Panels Needed: This is derived by dividing the total system wattage by the wattage of an individual panel. This gives you a practical number for installation.
- Estimated Total System Cost: A rough estimate based on the industry average cost per watt. This figure does not include potential incentives, tax credits, or rebates, which can significantly reduce the final cost.
- Estimated Annual Energy Production: The total kWh your system is expected to produce over a year.
- Estimated Annual Savings: How much you might save on your electricity bill annually based on your current electricity cost and the estimated annual production.
Next Steps
This calculator provides a good starting point, but for an accurate assessment and quote, it's essential to consult with professional solar installers. They can perform a detailed site evaluation, consider your specific roof characteristics, local regulations, available incentives, and provide a precise system design and cost estimate tailored to your needs.