Solar Panel kWh Production Calculator
Estimate the daily, monthly, and annual electricity production of your solar panel system with this easy-to-use calculator. Understanding your potential kWh output is crucial for sizing your system, evaluating savings, and planning your energy independence.
Estimated Solar Production:
Daily Production: 0.00 kWh
Monthly Production: 0.00 kWh
Annual Production: 0.00 kWh
Understanding Your Solar Panel kWh Production
Estimating the kilowatt-hour (kWh) production of a solar panel system is a fundamental step for anyone considering or owning solar energy. This calculation helps you understand how much electricity your system can generate, which is vital for assessing potential savings, system sizing, and return on investment.
How the Calculator Works
Our Solar Panel kWh Production Calculator uses key variables to provide a realistic estimate of your system's output:
- Number of Solar Panels: This is the total count of individual solar panels in your array. More panels generally mean higher overall system wattage and production.
- Individual Panel Wattage (Watts): Each solar panel has a rated power output, typically ranging from 300W to 500W or more. This value represents the panel's power generation under standard test conditions.
- Average Daily Peak Sun Hours: This is a crucial factor representing the equivalent number of hours per day when sunlight intensity averages 1,000 watts per square meter. It's not simply the total hours the sun is up, but rather a measure of the usable solar resource. This value varies significantly by geographic location and time of year. For example, a sunny region might have 5-6 peak sun hours, while a cloudier region might have 3-4.
- System Derate Factor (%): Also known as the performance ratio or system loss factor, this percentage accounts for various real-world inefficiencies that reduce a solar system's actual output compared to its theoretical maximum. These losses include:
- Temperature losses (panels are less efficient when hot)
- Wiring losses
- Inverter efficiency losses (DC to AC conversion)
- Shading (even minor shading can have a significant impact)
- Dust and dirt accumulation
- Panel degradation over time
The Calculation Formula
The calculator uses the following simplified formula:
Total System Wattage = Number of Panels × Individual Panel Wattage
Daily kWh Production = (Total System Wattage × Average Daily Peak Sun Hours × System Derate Factor) / 1000
The division by 1000 converts the result from Watt-hours (Wh) to kilowatt-hours (kWh).
Monthly kWh Production = Daily kWh Production × 30.44 (average days in a month)
Annual kWh Production = Daily kWh Production × 365
Example Scenario:
Let's say you have:
- 12 Solar Panels
- Each rated at 380 Watts
- Your location gets an average of 5.0 Peak Sun Hours per day
- You estimate a System Derate Factor of 78%
Calculation:
- Total System Wattage = 12 panels × 380 W/panel = 4560 Watts
- Daily kWh Production = (4560 W × 5.0 hours × 0.78) / 1000 = 17.784 kWh
- Monthly kWh Production = 17.784 kWh/day × 30.44 days/month = 541.29 kWh
- Annual kWh Production = 17.784 kWh/day × 365 days/year = 6491.16 kWh
This means your system could potentially generate around 17.78 kWh per day, over 541 kWh per month, and nearly 6,500 kWh annually, providing a significant portion of a typical household's electricity needs.
Factors Affecting Actual Production
While this calculator provides a strong estimate, actual production can vary due to:
- Weather Variability: Daily and seasonal changes in cloud cover, rain, and snow.
- Seasonal Changes: Shorter days in winter mean fewer peak sun hours.
- Shading: Trees, chimneys, or nearby buildings can cast shadows.
- Panel Orientation and Tilt: Optimal angles maximize sun exposure.
- Maintenance: Keeping panels clean can improve efficiency.
- Degradation: Solar panels slowly lose efficiency over their lifespan.
Use this tool as a starting point for your solar energy planning, and consult with a professional solar installer for a precise site-specific analysis.