How to Determine How Many Solar Panels You Need

Thinking about installing solar panels? One of the most common questions homeowners ask is: How many panels do I need? While it may seem complicated, calculating your solar energy needs is simpler than you think. Let’s break it down step by step with a real example.

Step 1: Estimate Your Annual Energy Consumption

First, determine how much electricity you currently use and account for any future additions that will increase your consumption.

• Current annual usage: 6,234 kWh
• Planned additions:
  • Electric car: +3,200 kWh
  • Heat pump HVAC: +2,700 kWh
  • Heat pump water heater: +1,500 kWh
• Total projected energy need: 13,634 kWh per year

Step 2: Determine the Solar Panel Output

Once you know how much electricity you need, the next step is calculating how much power your solar panel system can generate.

• Planned system: 21 REC405AA Pure panels (each 405W)
• Total DC output: 8.505 kW (8,505W)
• Estimated AC output (after efficiency loss): 7.12 kW (~83.5% efficiency)

Step 3: Compare Solar Production with Energy Needs

Your solar system should generate enough electricity to cover your projected consumption.

• Expected solar production: 14,200 kWh per year
• Projected usage: 13,634 kWh per year
• Surplus energy: ~566 kWh per year

With this setup, your solar system should meet your energy needs while generating some excess electricity.

Step 4: Key Considerations Before Installing Solar Panels

While this calculation gives you a solid estimate, keep in mind a few important factors:

• Seasonal Variability: Solar panels produce more energy in summer and less in winter.
• Panel Efficiency Loss: Over time, solar panels experience slight degradation in efficiency.
• Battery Storage vs. Net Metering: If your system generates excess energy, consider whether you’ll store it in a battery or send it back to the grid through net metering.

By following these steps, you can confidently size your solar panel system and take control of your energy future. 🌞

  Author: Susanna Leung

Susanna Leung’s goal as a real estate professional with Haylen Group is to help her first-time home buying clients find that perfect home where their families can grow, thrive, and live their dreams in the United States. She applies her experience in remodeling, resource networking, negotiations, and advanced marketing to provide her clients with dedicated, full coverage service.