The article considers internal adjustable sun-protecting jalousies from their different functional efficiency pant of view. It is noted, that besides their main sun-protective function, adjustable jalousies possess some other functions, depending on the position of their horizontal planks. These functions can be successfully used for microclimatic internal environment creation of comfortable. These are natural lighting function, psychological contract with surrounding environment function and function of visual isolation, i.e. “privacy”. and so on. All the above functions usually have maximum efficiency of their qualities in the case of their individual consideration. This, as a rule, is not practically reasonable. That is why this work is aimed on optimum combination of the man functional characteristics of horizontal sun-protecting jalousies under necessity of their mutual consideration, i.e. in achievement of their functional universality.

Keywords: sun-protecting devices, horizontal jalousies, functional characteristics, comfort of internal environment, optimization, insolation, visual comfort, functional universality, natural lighting