1. What is a Solar Panel Size Calculator?

Definition: This calculator estimates the required solar panel size (in watts) based on your energy needs, available sunlight hours, and system performance.

Purpose: It helps homeowners and solar installers determine the appropriate solar panel capacity for specific energy requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P \) — Solar panel size (watts)
• \( Load \) — Daily energy requirement (watt-hours)
• \( H \) — Peak sunlight hours per day
• \( PR \) — Performance ratio (system efficiency)

Explanation: The energy requirement is divided by the product of sunlight hours and performance ratio to determine the needed panel wattage.

3. Importance of Solar Panel Sizing

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

4. Using the Calculator

Tips: Enter your daily energy needs in watt-hours, average sunlight hours (default 5), and performance ratio (default 0.75). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical performance ratio?
A: Most systems have a PR between 0.7-0.8, accounting for losses from temperature, wiring, inverters, etc.

Q2: How do I find my daily energy requirement?
A: Check your electricity bill for kWh usage and convert to Wh, or sum the wattage × hours of all devices you'll power.

Q3: What affects sunlight hours?
A: Location, season, weather, and panel orientation/tilt all impact daily sunlight hours.

Q4: Should I round up the calculated size?
A: Yes, it's recommended to round up to the nearest standard panel size and add 10-20% for future needs.

Q5: Does this include battery storage?
A: No, this calculates panel size only. Battery requirements depend on nighttime usage and backup needs.