Nanofluids enhance heat transfer and reduce energy losses in thermal systems by increasing thermal conductivity and intensifying disturbances in the boundary layer. Their performance depends on the type of base fluid, the concentration and properties of nanoparticles, and operating conditions such as temperature and flow velocity. In this study, the effect of operational parameters on the heat transfer performance of an iron oxide nanofluid was investigated. The flow velocity ranged from 17 to 34 cm•s⁻¹, the surface heat flux from 18 to 93 W•m⁻², and the bulk fluid temperature from 30 to 60 °C. Nanoparticles were dispersed at weight fractions of 0.001, 0.005, and 0.01, and sodium dodecyl sulfate (SDS) was used as a surfactant to ensure stability. The results showed that at bulk temperatures above 40 °C, the addition of iron oxide nanoparticles significantly improved the thermal performance compared with water. Moreover, increasing the flow velocity and bulk temperature enhanced the heat transfer coefficient of the nanofluid. The results also indicate that optimizing nanoparticle concentration according to operating conditions is essential.