Planet Solar: How Does My Solar Contractor Determine My System Size?

September 11, 2023

The Right Solar System for Optimal Home Energy Use

Determining the right size for your solar system is key to having an energy-efficient home and realizing your green living goals. This can be a daunting task. Many homeowners struggle with this crucial step, often feeling overwhelmed by the technical jargon and complex calculations involved.

If you are not sure how to determine the ideal size for your solar system, stay tuned.

How Lifestyle/Future Plans Shape Your Solar System Size

The size of your solar system is determined by several factors, but first and foremost is your current annual electric consumption at the house. Secondly, your solar contractor will want to know of any projected lifestyle plans for the household, such as family members moving in or out or renovations that affect energy consumption (such as an addition). The addition of an electric vehicle (EV) will also have a dramatic effect on energy needs.


Your Retirement Life Powered by Solar Energy, For Example

As you transition into retirement, your daily routine and energy usage patterns undergo substantial changes. With more time spent at home, factors like heating, cooling and electronic device usage will evolve.


By considering your anticipated energy consumption during retirement, you can make informed decisions about the size and capacity of your solar energy system. Thoughtful retirement planning thus enables you to tailor your solar panel investment to match your post-work lifestyle, optimizing energy production and consumption for a more sustainable and financially viable future.


Fueling Electric Vehicles with Sunlight

Owning an electric vehicle (EV) can significantly influence the number of solar panels needed for your home. The integration of an EV introduces an additional electricity demand that, if not properly managed, could strain your household energy consumption and budget.

However, this scenario also presents an opportunity for synergy between sustainable technologies. By strategically coordinating the charging of your EV with the availability of sunlight, you can maximize the utilization of solar energy to power both your home and your vehicle.


Adding a Solar Battery to Your System is Important

Are you thinking about incorporating a solar battery into your solar power setup? Here is why it might be an essential addition. Solar batteries, also known as energy storage systems, offer a groundbreaking solution to address the intermittent nature of solar energy production. While solar panels generate electricity during the day, excess energy often goes unused or is fed back into the grid. By integrating a solar battery, you can capture and store surplus energy generated during sunny periods, which can then be utilized during the evenings, cloudy days or blackouts.


Solar batteries contribute to the overall stability of the power grid by allowing homeowners to discharge stored energy during peak demand hours, reducing strain on the system. Embracing solar battery technology can thus elevate the efficiency and reliability of your solar power system, offering both economic and environmental benefits in the pursuit of a more sustainable energy future.


The Impact of Batteries on a Solar System Size:

  • Your chosen battery capacity will affect how much excess solar energy can be stored.
  • If planning ahead towards retirement or considering buying an electric vehicle (both scenarios potentially increasing average daily use), having ample storage becomes crucially important.
  • Batteries require space allocation, usually in your garage – another aspect influencing a decision to add batteries.

Maximizing Roof Space for Optimal Solar Installation

The more sunlight your solar system receives, the greater its power generation potential. Therefore, optimizing roof space becomes a critical factor when planning your home’s solar array.


Sun Exposure: The Key to Maximizing Your Solar System’s Power Generation

Your panels’ efficiency soars with increased sun exposure. Hence, understanding how much direct sunlight hits different parts of your property throughout the year can help you make informed decisions about panel placement and ultimately maximize energy production.

In Southern and Central California, south-facing roofs are ideal as they typically receive more sunlight. This means that if properly utilized, these areas could significantly boost your system’s output while reducing its carbon footprint. East and west-facing solar panels produce only slightly less energy than south-oriented solar panels.

To assist in determining optimal installation spots on your roof based on sun exposure patterns specific to your location, your solar contractor will utilize solar mapping tools. These handy resources provide comprehensive data regarding annual sunshine distribution across various sections of properties – an invaluable aid when aiming to harness the maximum potential from the big open space above.

A Simple Formula for Estimating Solar System Size

If you are considering getting solar panels for your home, understanding how to use the formula to estimate the number of solar panels you might need is a helpful starting point. This formula allows you to calculate a rough estimate of the solar panel quantity based on your average daily energy consumption and the environmental conditions of your home’s location.

First, you will want to determine your daily energy consumption, which is the amount of electricity your home consumes on a given day. This information can be gleaned through an analysis of your electricity bills and is measured in kilowatt-hours (kWh). Once you have this value, you’re ready to proceed.


Next, research the peak sunlight hours for your geographical area. Peak sunlight hours refer to the hours during the day when solar panels receive the most intense sunlight and produce the maximum amount of electricity. This value can vary depending on your location, the time of year, and any potential shading. For the Coachella and Central Valleys, the average is between six and seven peak hours.

Last, consider panel efficiency. Panel efficiency represents how well the solar panels convert sunlight into electricity. Efficiency is expressed as a decimal, such as 0.18 for 18%. This factor takes into account the inherent losses and capabilities of the panels.

Using the formula “Number of Solar Panels = (Average Daily Energy Use) / (Peak Sunlight Hours) / (Panel Efficiency),” you can input these values to estimate the number of solar panels you might need to cover your energy needs.


Keep in mind that this formula offers a basic estimation and does not account for variables like shading, panel angle and system losses. To get a more precise assessment, consulting with a professional solar installer or using specialized solar calculators is recommended. This formula serves as an initial step in your journey toward understanding the potential requirements of a solar panel system for your home.

In Conclusion

Understanding your solar system size is a game-changer. Figuring out your solar system size is critical for optimizing energy efficiency in the home.

You have learned how to calculate your average daily energy usage – an essential first step. Your lifestyle and future plans also play a huge role in determining the right system size for you.


Adding a solar battery can lessen your grid dependence and provide backup power during outages for lights and essential appliances.


The importance of maximizing roof space for optimal installation was discussed, along with factors like sun exposure and roof orientation that affect this decision.

You can undertake all this research yourself, OR you can bypass all this work by consulting with a local, experienced and professional solar contractor who will undertake the analysis and then provide you with a customized solar proposal.