A “15W” label does not reveal an LED’s real heat load. This article explains how to trace junction-to-ambient heat flow, evaluate temperature effects on optical output and reliability, verify cooling and driver design, interpret certification scope, and demand traceable worst-case test evidence for phototherapy devices.

This article explains how LED junction temperature causes irradiance and wavelength drift in red light therapy panels. It presents key formulas, thermal-resistance estimation methods, corrected dose calculations, measurement guidelines, common dosing errors, and practical specifications buyers should request when evaluating panel performance.