Solar PV System Estimator
Use this calculator to estimate the size of the solar PV system you might need, its potential energy production, annual savings, and approximate installation cost based on your energy consumption and local conditions.
Enter your average daily electricity usage in kilowatt-hours.
This is the equivalent number of hours per day when solar irradiance averages 1,000 watts per square meter. Varies by location and season.
Typical wattage for a single solar panel (e.g., 350W, 400W).
Accounts for real-world losses (temperature, wiring, dust, inverter efficiency). Typically 75-85%.
Your average cost per kilowatt-hour from your utility company.
Average cost to install solar per watt of capacity (e.g., $2.50 – $4.00).
Calculation Results:
Estimated Required System Size:
Estimated Number of Panels:
Estimated Annual Energy Production:
Estimated Annual Electricity Savings:
Estimated Total System Cost:
Understanding Your Solar PV System Needs
Going solar is a significant investment that can lead to substantial long-term savings and environmental benefits. A Solar PV (Photovoltaic) system converts sunlight directly into electricity using solar panels. Understanding how much electricity you consume and the solar potential of your location are crucial first steps.
How the Calculator Works
This calculator helps you estimate key metrics for a potential solar installation. Here's a breakdown of the inputs and what they mean:
- Average Daily Energy Consumption (kWh): This is the most critical input. It represents how much electricity your household or business uses on an average day. You can usually find this on your electricity bills, often listed as "kWh used" or similar. The goal of a solar system is typically to offset a significant portion, if not all, of this consumption.
- Average Daily Peak Sun Hours (hours): Not all sunlight is equal. Peak sun hours represent the intensity and duration of sunlight that is most effective for solar panel generation. It's the equivalent number of hours per day when solar irradiance averages 1,000 watts per square meter. This value varies significantly by geographic location, season, and local weather patterns. 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 (Watts): This refers to the power output rating of a single solar panel under standard test conditions. Modern residential panels typically range from 300W to 450W. Higher wattage panels mean fewer panels are needed for a given system size.
- System Derating Factor (%): Solar panels rarely perform at their absolute maximum rated capacity in real-world conditions. The derating factor accounts for various losses, including temperature effects (panels are less efficient when hot), wiring losses, dust accumulation, shading, and inverter efficiency. A typical derating factor ranges from 75% to 85%.
- Average Electricity Cost ($/kWh): This is the price you pay per kilowatt-hour for electricity from your utility company. This input is essential for calculating your potential annual savings.
- Estimated Installation Cost per Watt ($/Watt): This is the average cost to purchase and install a solar system, expressed per watt of capacity. This figure includes panels, inverters, mounting hardware, labor, permits, and other associated costs. It can vary widely based on location, installer, system size, and equipment quality.
Interpreting Your Results
- Estimated Required System Size (kW): This is the total DC (Direct Current) power capacity your solar array needs to generate enough electricity to meet your daily consumption, considering your peak sun hours and system losses.
- Estimated Number of Panels: Based on the required system size and the wattage of individual panels, this tells you approximately how many panels you'll need. This helps in planning roof space.
- Estimated Annual Energy Production (kWh/year): This is the total amount of electricity your solar system is expected to generate over a year.
- Estimated Annual Electricity Savings ($/year): By multiplying your annual production by your electricity cost, this figure shows how much you could potentially save on your electricity bills each year.
- Estimated Total System Cost ($): This provides a rough estimate of the upfront investment required for your solar system, based on the required system size and the cost per watt.
Example Scenario:
Let's say a homeowner uses 25 kWh of electricity per day, lives in an area with 4.5 peak sun hours, plans to use 400W panels, expects an 80% system derating factor, pays $0.15/kWh for electricity, and estimates an installation cost of $3.00/Watt.
- Required System Size: (25 kWh / 4.5 hours) / 0.80 = 6.94 kW
- Number of Panels: (6.94 kW * 1000) / 400W = 17.35, so approximately 18 panels.
- Annual Production: 6.94 kW * 4.5 hours/day * 365 days/year * 0.80 = 9,110 kWh/year
- Annual Savings: 9,110 kWh * $0.15/kWh = $1,366.50/year
- Total System Cost: 6.94 kW * 1000 * $3.00/Watt = $20,820
These estimates provide a solid starting point for further research and discussions with solar installers. Always get multiple quotes and detailed energy audits for precise planning.