The work aims to develop a light-vent unit combining light pipe technology and passive stack ventilation by utilising the light pipe as an exhaust stack. This system can be further integrated with a novel design of heat pipe to heat or cool the building. The work contains several aspects related to the use of light pipes and stack ventilation. A study of the statistical information on the main building types and their morphology in several European countries has helped to determine the most suitable regions for this technology. It seems, that the most potential building types are educational, office and retail buildings. In order to enhance the natural stack ventilation and to prevent reverse flow, a wind terminal is installed on the top of the light-vent pipe. Several types of terminals have been investigated. The best performing ones, a variant of the h-pot and the umbrella type have been investigated further. The umbrella type gives slightly higher air flows but both types have a positive effect on the functioning of the ventilation. Also the development of a light collector is included in the work. Results of modelling have shown, that for the concept to be economically feasible, a well performing collector is essential. It seems, that static collectors are not able to guide enough light into the pipe and that a one-axis or two-axis tracking system is needed.