More than ten, but not more than forty. We realize that’s a big range, but there’s no such thing as a one-size-fits-all answer when it comes to solar: the number of panels you should put is determined by how much sun your property receives, your energy consumption, and the amount of space you have available for the installation. The majority of people create a system that can generate as much of their electricity as feasible (this is how you save the most money!)