When homeowners in San Diego County start doing their solar research, a common question they have is: What is the average sized solar system in their area? This is a complex question, as the average size of a solar installation in any given community is based on a number of factors including: median home value in that area, distance from the coast, density of homes in the area, etc. Despite the complexity of this question, we wanted to attempt to address it. But instead of looking at San Diego in general, we looked at 20 of the top solar municipalities in San Diego County, and, by tapping into our database of over 10,000 installations, we calculated the average system size (in kW not number of panels) for each of the communities. We also looked at how average home values and distance from the coast correlated with system sizes, to see how influential those factors were.
What determines the size of a solar system?
Before we begin, we have to define the term “size” when it comes to solar systems. When we talk about the “size” of a solar system, we are not speaking about literal physical size – we are talking about electrical rating or output in kilowatts; however, sometimes a higher output system will also be physically bigger. But since modern panels produce more kW per panel than older ones, a physically smaller system (in square feet or number of panels) can now create the same amount of electricity (in kW) as older systems that simply take up more space. So just because a solar system is physically “bigger”, doesn’t mean it has a larger electrical rating in output.
Our methodology for this study was simple: we took our database of thousands of installations throughout Southern California and sorted them by the number of installations we have completed in that area. We then calculated the average of all the installations in the area.We also used data from Zillow on the average value of homes in each of these areas, and sorted them by that number.
So, as a disclaimer, this data is based on our own customer data, not data from all solar installers in the area. For this reason, the data may not be completely universal.
Many critics of solar energy say that solar panels, due to their cost, are only a good solution for wealthy homeowners. If these critics are correct, you would expect that the higher the home value, the larger the solar energy system. However, we’ve sold a lot of solar to all areas of San Diego County and to all demographic groups. What we ourselves would expect (based on our experience) is that the farther the community is from the coast, the higher the electric bill and therefore, the larger the system size. Let’s take a look at the data to see if it backs up those assumptions.
Our findings somewhat surprised us and defied some of our expectations – but when you look at the different factors at play, mostly make sense. We ordered the cities in ascending order by home values, to get an idea of any correlations that exist in size as home values go up.