A new technique is developed to directly grow Cu nanowire (CuNW) on Si substrate with electro-chemical deposition to produce height-controlled hydrophilic nanowired surfaces for enhancing pool boiling performance. For broader heat transfer applications, CuNW and Si nanowires (SiNW) with various nanowire heights were fabricated and examined under pool boiling with water. The heat transfer performance of the samples with NW arrays is enhanced with increasing NW heights regardless of the NW materials. The surface with the tallest NW structure (35 μm-tall SiNW) yielded a heat flux of 134 W/cm 2 at 23 K wall superheat, about 300% higher than a plain Si surface at the same wall superheat. ► A new technique is developed to directly grow copper nanowire on silicon substrate. ► Increasing nanowire height improves boiling performance. ► Optimal results were obtained in pool boiling with 35 nm long nanowires.