Abstract The experimental and numerical analyses of the standard fume hood features in order to determine the nature of the flow phenomena within the working chamber are presented and studied in the paper. The experiments were carried out for three characteristic heights of the vertical sliding sash, i.e., the lowest (closed), working and the highest (fully opened) heights. The air flow parameters such as: mass flow rate, local distribution of velocity at the exhaust plenum and inlet and pressure drop were measured and analyzed. Assuming isothermal, incompressible and turbulence flow of the air treated as ideal gas, the numerical model based on the continuity and momentum equations was proposed and solved using the Finite Volume Method (FVM). The numerical model was validated against the obtained experimental results. The goal of the numerical simulations was to investigate the flow structure and condition inside the fume hood for different heights of a vertical sliding sash. The obtained numerical results indicated the intensified air recirculation zones within the fume hood chamber and showed the complicated nature of the flow. The conclusions and fume hood design guidelines aimed at reducing the size of the recirculation zones and thus reducing the noise and power needed to drive the exhaust fan were determined. On the basis of the performed calculations four modifications of the fume hood design were proposed and numerically analyzed. Finally, the reduction of the recirculation zones therefore a decrease of pressure drop by 30.5% was achieved.