This invention solves the problem of introducing an invisible system designed to prevent the possibility of developing thermal convection (in gaseous medium) into the space contained between transparent sheets, especially panes, filled with transparent colourless gas, or designing the geometry of the entire space in such a way, as to prevent the possibility of developing such convection. The system of gaseous thermal insulation has an internal arrangement suppressing thermal convection, in the form of at least one chamber (3) defined by transparent walls (2) parallel to each other and located between the outer panes (1) and inclined to the horizontal, with the bottom edge of the chamber (3) bound along its longer edge with the colder pane, i.e., the one located in the zone of a lower temperature, whereas the upper edge of the chamber is bound with the warmer pane, i.e., the one located in the zone of a lower temperature.