<p>We investigate the performance of a quantum non-Hermitian sensor based on a two-level non-Hermitian system, modeled as a spinless fermion on two lattice sites, for quantum thermometry. The fermion is coupled to a Hermitian bath at thermal equilibrium. Using Hilbert-Schmidt speed (HSS), we evaluate the metrological precision of this sensor. Our findings highlight the intricate relationship between non-Hermitian parameters and the sensor’s performance, offering valuable insights for optimizing quantum sensor design. Furthermore, we explore the potential of this sensor in different scenarios, considering the effects of environmental noise and imperfections. The sensitivity and accuracy of the quantum non-Hermitian sensor near the exceptional point are suppressed, limiting its ability. We demonstrate the critical impact of non-Hermitian strength on the sensor’s sensitivity and accuracy, which achieves the highest sensitivity for temperature estimation in the broken symmetry phase. Notably, the proposed quantum non-Hermitian sensor attains high precision at low temperatures. Our results pave the way for developing robust and high-precision quantum sensors for a wide range of applications, pushing the boundaries of quantum metrology and sensing technologies. These sensors have potential applications in diverse fields like advanced microscopy, positioning systems, and communication technology.</p>