This paper conducts a 3D numerical analysis of a hybrid photovoltaic thermal (PVT) solar system, incorporating a new channel-shaped heat exchanger design. The aim is to examine the impact of the materials used in the manufacture of the heat exchangers on the performance of these systems, focusing on aluminum, copper and PMMA polymer. The heat exchanger, integrated directly into the back of the photovoltaic module, uses water as the heat transfer fluid. The 3D numerical model, developed with COMSOL Multiphysics® software and based on the finite element method (FEM), is validated by comparing its results with experimental and numerical data taken from the literature. This study showed that the use of PMMA polymer as an exchanger material presents poor performances, making it unsuitable for heat absorbers. In addition, the use of copper and aluminum as heat exchanger materials shows similar performance, suggesting that aluminum could be a lighter and cheaper alternative.