1. What is a Solar Panel Wattage Calculator?

Definition: This calculator estimates the required solar panel wattage based on your daily energy needs, available sunlight hours, and system efficiency.

Purpose: It helps homeowners and solar installers determine the appropriate solar panel size for a given energy requirement.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_w \) — Solar panel wattage (watts)
• \( E_{kWh} \) — Daily energy requirement (kilowatt-hours)
• \( t_{sun} \) — Average daily sunlight hours (hours)
• \( \eta_{solar} \) — System efficiency factor (0-1)

Explanation: The energy requirement is converted to watt-hours, then divided by the product of sunlight hours and system efficiency to account for energy losses.

3. Importance of Solar Panel Sizing

Details: Proper solar panel sizing ensures your system meets energy needs without over-investing in unnecessary capacity, optimizing both performance and cost.

4. Using the Calculator

Tips: Enter your daily energy needs in kWh, average sunlight hours (default 5), and system efficiency (default 0.75). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical system efficiency factor?
A: Most residential systems have 70-80% efficiency (0.7-0.8) accounting for inverter losses, wiring, temperature, and other factors.

Q2: How do I find my daily energy needs?
A: Check your electricity bill for monthly kWh usage and divide by 30, or use an energy monitoring device.

Q3: What are average sunlight hours in my area?
A: Consult solar maps or local weather data. Most areas range from 3-7 peak sun hours daily.

Q4: Does this include battery storage?
A: No, this calculates the panel size needed to meet daily needs. Add 20-30% for battery systems to account for charging/discharging losses.

Q5: How do I convert this to number of panels?
A: Divide the total wattage by your chosen panel's wattage (e.g., 300W panels). Round up to whole panels.