Solar Panel Sizing Calculator

Estimate the ideal solar panel system size based on your energy consumption and location.

Disclaimer: This calculator provides estimates only and should not replace professional consultation. For accurate sizing and installation requirements, please consult with a certified solar energy professional.

Monthly Energy Consumption (kWh)

Daily Sunlight Hours

Solar Panel Wattage (W)

System Efficiency (%)

About Our Solar Panel Sizing Calculator

Our Solar Panel Sizing Calculator helps you estimate the size of the solar energy system needed to meet your electricity requirements. By considering your energy consumption, location-specific sunlight hours, and system parameters, it provides a preliminary assessment of your solar power needs.

Why Size Your Solar System Correctly?

Properly sizing your solar panel system is crucial for maximizing energy efficiency and return on investment. An undersized system won't meet your energy needs, while an oversized system can lead to unnecessary expenses. Our calculator helps you find the sweet spot by calculating your specific requirements based on actual energy consumption data.

How Solar Sizing Works

The process for sizing a solar panel system involves several key factors:

System Size (kW) = (Daily Energy Requirement × 1.25) ÷ (Peak Sun Hours × System Efficiency)

Where:

Daily Energy Requirement is your monthly consumption divided by 30
1.25 is a safety factor to account for system losses
Peak Sun Hours is the average daily sunlight hours in your location
System Efficiency accounts for various losses in the system

Key Features:

Calculate recommended system size based on your actual energy consumption
Estimate the number of solar panels needed for your system
Determine approximate roof space requirements
Predict daily and monthly energy production
Adjust calculations for different solar panel types and efficiencies

How to Use:

Enter your average monthly electricity consumption in kilowatt-hours (kWh) from your utility bill
Input the average daily peak sun hours for your location
Specify the wattage of the solar panels you plan to use
Adjust the system efficiency if needed (default is 80%)
Click "Calculate Solar System" to see your results

Factors Affecting Solar Panel Performance:

Geographic Location: Sunlight intensity and duration vary by location, affecting system output.

Roof Orientation: South-facing roofs (in the Northern Hemisphere) typically receive the most sunlight.

Roof Angle/Tilt: The optimal angle is typically equal to your latitude for year-round production.

Shading: Trees, buildings, or other obstructions can significantly reduce system output.

Panel Efficiency: Higher efficiency panels produce more power per square foot but may cost more.

Temperature: Solar panels are less efficient in very high temperatures.

Types of Solar Panels

There are three main types of solar panels with different efficiency rates and costs:

Monocrystalline: Highest efficiency (15-22%), longest lifespan, but more expensive.
Polycrystalline: Moderate efficiency (13-16%), more affordable than monocrystalline.
Thin-Film: Lowest efficiency (10-12%), least expensive, requires more space but works better in high temperatures and low light.

This calculator is perfect for homeowners, business owners, solar enthusiasts, and anyone interested in renewable energy solutions. While it provides a valuable starting point, we recommend consulting with a professional solar installer for a detailed assessment of your specific needs.

Frequently Asked Questions

How accurate is this solar calculator?

This calculator provides estimates based on the information you provide and typical solar performance parameters. While it gives a good starting point for system sizing, actual performance will depend on many factors including exact location, installation quality, weather patterns, and equipment specifications. For precise calculations, we recommend consulting with a solar professional who can perform a site-specific assessment.

How do I find my average peak sun hours?

Peak sun hours vary by geographic location. You can find this information from solar irradiance maps, local weather data, or solar resource databases. In the United States, the National Renewable Energy Laboratory (NREL) provides this data. Generally, locations in the southwest US receive 5-7 peak sun hours daily, while northeast regions might average 3-5 hours. If unsure, using 4-5 hours provides a reasonable estimate for many temperate locations.

Will a solar system eliminate my electric bill entirely?

While a properly sized solar system can significantly reduce or eliminate your electricity costs, most grid-tied systems will still have some minimal utility connection fees. Additionally, if your system doesn't include battery storage, you'll still rely on grid power during nighttime or cloudy periods. Net metering policies (where available) allow you to feed excess power back to the grid during sunny periods, potentially offsetting these costs. Check with your local utility for specific policies and fees.