The 120 Rule for Solar: What It Is, How to Calculate It, and Where It Applies (US and Pakistan, 2026)
You get a solar quote, and then the installer says, “Your panel might fail the 120 rule.” In the US that can mean a panel upgrade costing thousands of dollars. In Pakistan, buyers hear the same term from installers and wonder if it applies to them at all. The 120 rule for solar (also called…