It has been reported that as much as 18% of a building’s energy use for heating or cooling can be related to infiltration, or the unintentional introduction of outside air into the buildings inside environment. One of the main sources of infiltration into a building is through its open doors. Especially in commercial buildings with high frequency door use. Thus, it is of great interest to reduce the door infiltration rate in order to decrease the buildings energy use. The research presented in this report aims to evaluate the infiltration blocking efficiency of a newly developed device. A small scale prototype of the device, which works by discharging and re-circulating air flow in the direction towards the door, will be thoroughly investigated in a series of experiments. The device performance and dependency on external conditions will be evaluated and the established relations will be used in the development of a control unit which aims to ensure optimum performance of the device.  During the initial literature study it was found that the main force driving infiltration was the differential pressure between the outside and inside of the building. By implementing pressure sensors in the devices’ control unit these values could be used to control the device fan speed and performance. The results show that the device has an energy saving potential of around 70% at wind speeds around 1.0 m/s. At higher wind speeds it was discovered that the required fan capacity might make the device practically un-feasible for real world application. Although, the method for the experiments was assessed to result in low efficiency values compared to a full-scale device operating in real world conditions. Furthermore, it is assumed that a detailed study of the devices’ aerodynamic properties could improve its efficiency and decrease the required fan capacity. Therefore, it is concluded that continuous development could result in a device with better performance and larger potential for a widespread implementation.