solar energy per square foot
Frequently people want to know how many solar panels they will need based on the size of their home. However, the amount of electricity you use is more important for solar electric system design than the square footage of your home. This is mainly because people’s use of electricity varies in so many different ways.
Same House, Different Energy Situations
For instance, let’s say two families live next door to each other in 2, 000 square foot homes. A young man lives in Home A with his fiancé; they both work long hours and often spend evenings out with friends. As a result, they don’t use much electricity and pay about $40 a month.
In Home B, two parents live with their two teenage children. They are either running the heater or air conditioner and use electricity to filter their pool, meanwhile the teenagers are always on their iPads, opening the refrigerator or watching TV. Since more people live in the house and their lifestyle requires more energy, their electricity bills run at about $325 a month.
Importance of Electricity Usage for Solar Panel Design
Even though they live in homes that are the exact same size, the family in Home B would most likely need to invest in more solar panels to bring down their electricity usage than the couple living in Home A. Even if the households were identical in electric consumption, one home may have better solar exposure or less shade than another, which can mean more or fewer panels.
Electricity usage is also important because most utility companies in Los Angeles and Orange County limit the size of your solar system based on the amount of energy you currently use. This number is usually determined by looking at how much electricity you have used in the last 12 months.
Just Moved or Building Your Home? Here’s How it Works
Of course, there are always some exceptions to the rule. If you have only lived in your home for a few months or want to install solar panels on a home in construction, then most utility companies let us estimate usage based on your home’s square footage.
As an example, LADWP calculates this type of average at 2 watts for every square foot. So, a 2, 000 square foot home would be allowed a solar array of 4, 000 watts. Depending on the type of panel that you choose, a system of this size would be anywhere from 12-18 solar panels. Keep in mind, this formula to estimate consumption varies depending on who provides your electricity.
Another exception is sometimes made for people who are anticipating that their electricity usage will go up. If you are planning to buy an EV (electric vehicle) or install central air, for example, we can estimate the additional usage and factor it into the solar panel design and cost. But, the utilities are sticklers! They will make us submit proof of purchase along with the solar system application.