In this contribution, we investigate the potential and the interest of the isogeometric analysis in the context of weakly compressible materials at large strains submitted to thermomechanical loading. Classical finite element models and isogeometric models are compared in term of accuracy, robustness and numerical efficiency. The application targeted in this study is the aging of elastomers under long term thermomechanical cycling. The problem is to obtain sufficiently accurate solutions for mechanical and thermal fields to avoid spoiling of the different associated physics.