Cost-effective photovoltaics (PVs) require a high energy yield with a long system lifetime. However, both are adversely affected by temperature. Here, we assess the economic impact of thermal effects on PV systems by establishing a temperature-dependent levelized cost of energy (LCOE) model. Using this model, we introduce an equivalent ratio (with the unit of absolute efficiency %/K) as a new metric that quantitatively translates the LCOE gain obtained by reducing the module temperature () to an equivalent absolute power conversion efficiency increase. The substantial value of motivates us to investigate the root causes of heating in solar cells and modules, with a focus on crystalline-Si (c-Si) PVs, given its market dominance. To link the heat analysis with , we establish and validate an opto-electronically coupled thermal model to predict . This modeling approach enables the quantification of possible ways to mitigate undesired heating effects.