July 5, 2026

You’re staring at a solar quote, or maybe a spec sheet an installer left on your kitchen table, and there it is — a little string of letters and numbers you didn’t ask for and don’t remember agreeing to learn: AM1.5. Right next to it, a wattage rating that sounds fantastic. 400 watts. 440 watts. […]

You’re reading through a solar panel spec sheet, or maybe a climate article, and you hit the phrase “solar constant.” It sounds like it should be one of those simple, self-explanatory science terms. Then you notice it’s described as varying slightly, and suddenly it doesn’t sound very constant at all. Here’s the short version: the