SUMMARY
The air quality of indoor spaces is the most significant parameter in providing a healthy living environment. Low indoor air quality (IAQ) leads to Sick Building Syndrome—one of the major reasons for labor loss in office buildings. The fundamental measure to ensure indoor air quality is ventilation, which includes two basic types: mechanical ventilation and natural ventilation. Natural ventilation is an exchange of stale indoor air with fresh outdoor air by means of a pressure difference due to wind and/or stack effect. Trickle Vents, known also as background ventilators, are natural ventilation devices which can be integrated into façades or window systems as an alternative to operable vents, specifically in high-rise buildings. The major design criteria of Trickle Vents are ventilation capacity, controllability, actuation, thermal insulation, air permeability, water tightness, climatic adaptation, security, and acoustic attenuation. Other important parameters in Trickle Vents design are positioning, equivalent area, and control strategy. This paper aims to review all these aspects, particularly with reference to building regulations and commercial products. Furthermore, simulation, experimental, monitoring, and survey studies of Trickle Vents are also discussed. This literature review is presented from the perspective of performance parameters, control strategies, positioning, etc., with an aim to provide a comprehensive overview of such technology.