In this paper, the insertion effect of a woven wire mesh to cross flow heat exchanger will be studied under steady state laminar flow conditions. 3-D numerical model was developed for the bare heat exchanger and the other wire mesh modules. The mesh wire diameter is 2.5 mm, porosity of 0.75, permeability of 10-10 and layer-to-layer spacings of (3,5,10,15,20 and 25 mm). Air flows with velocity range up to 3.5 cm/s through rectangular duct of 50 cm X 25 cm with inlet temperature of 25 o C before it is heated with corrugated water tube (19 mm in diameter) with hot water inlet velocity of 1 m/s and temperature of 50 o C. The thermal and hydraulic performance were evaluated. Results showed that an enhancement in overall heat transfer coefficient was achieved of 250 % for the 3 mm spaced module while the air pressure drop increases significantly.