Recently, the trend of high heat generation rates of devices, including motors, power electronics, and data centers, has increased the demand for high-efficiency cooling techniques. Boiling is a commonly utilized phenomenon to realize high-efficiency cooling techniques since it can transfer a large amount of heat based on a small temperature difference. Moreover, with the need for integration and miniaturization of devices, immersion cooling technology was proposed, which put the heating parts or the entire device into the dielectric fluid. Such kind of method greatly reduces the heat resistance between the heat generation parts and the cooling fluid, making it possible to cool in a limited space efficiently. However, as the newly developed working fluids, some of the dielectric fluids' essential characteristics are still not well known, especially in conditions of low saturation temperatures/pressures. In addition, the boiling heat transfer under low saturation temperatures/pressures cannot be correctly predicted by the available empirical formulas. Therefore, by taking Novec 7100 as a representing dielectric fluid for the immersion cooling technology, the experimental study was carried out on heat transfer characteristics during pool boiling. An airtight experimental system was established, and the experiments were performed for the saturation temperatures ranging from -15 to 20 °C. Based on the experimental results, it was shown that the boiling heat transfer of Novec 7100 deteriorates with the decreasing saturation temperature. The experimentally measured values of heat transfer coefficient, heat flux, and critical heat flux were higher than the predicted values of the empirical formulas, indicating the underestimation of the boiling heat transfer of Novec 7100 based on the empirical formulas.