An aluminium carpentry system comprising a frame, a sash movably mounted in the frame, a glazing unit, glazing clips and at least one hardware fitting, wherein the frame consists of an external profile and an internal profile, which are connected via plastic thermal strips (103, 104), and a central insulation element is mounted on the frame at the side facing the sash in a closed position of the system, the sash consists of an external profile and an internal profile, which are connected via plastic thermal strips (203, 204), wherein the internal profile of the sash at the side facing the frame in a closed position of the system has a hardware groove having substantially U-shaped cross-section, formed entirely of plastic and set in a recess in the internal profile of the sash, while at the opposite side it has a clamping groove for fixing the glazing clips, the glazing unit comprising at least one glass pane is mounted in a mounting seat formed between the external profile of the sash provided with form-fitted external glazing gaskets, the external plastic thermal strip of the sash and the glazing clips provided with form-fitted internal glazing gaskets and mounted in the clamping groove of the internal profile of the sash, at least one hardware fitting is slidably placed in the hardware groove of the internal profile of the sash, at the edge facing the frame the internal profile of the sash is provided with form-fitted internal rebate gaskets, by means of which it sealingly engages the internal profile of the frame in a closed position of the system, characterized in that the central insulation element is in form of a plastic moulding, which is form-fitted in corresponding projections at the frame surface from the side facing the sash in a closed position of the system, wherein between the plastic moulding surface and the internal plastic thermal strip of the sash there is an air gap, the outlet of which from the outside of the system in cross section view is closer to the sash than its outlet from the inside of the system, whereby the plastic moulding is mounted through clicking or sliding into guides formed by corresponding projections at the frame surface from the side facing the sash in a closed position of the system, and the width of the air gap is from 2.5 to 4 mm, at the edge facing the sash the external profile of the frame is provided with form-fitted external rebate gaskets, by means of which it sealingly engages the external profile of the sash in a closed position of the system. wherein the frame consists of an external profile and an internal profile, which are connected via plastic thermal strips (103, 104), and a central insulation element is mounted on the frame at the side facing the sash in a closed position of the system, the sash consists of an external profile and an internal profile, which are connected via plastic thermal strips (203, 204), wherein the internal profile of the sash at the side facing the frame in a closed position of the system has a hardware groove having substantially U-shaped cross-section, formed entirely of plastic and set in a recess in the internal profile of the sash, while at the opposite side it has a clamping groove for fixing the glazing clips, the glazing unit comprising at least one glass pane is mounted in a mounting seat formed between the external profile of the sash provided with form-fitted external glazing gaskets, the external plastic thermal strip of the sash and the glazing clips provided with form-fitted internal glazing gaskets and mounted in the clamping groove of the internal profile of the sash, at least one hardware fitting is slidably placed in the hardware groove of the internal profile of the sash, at the edge facing the frame the internal profile of the sash is provided with form-fitted internal rebate gaskets, by means of which it sealingly engages the internal profile of the frame in a closed position of the system, characterized in that the central insulation element is in form of a plastic moulding, which is form-fitted in corresponding projections at the frame surface from the side facing the sash in a closed position of the system, wherein between the plastic moulding surface and the internal plastic thermal strip of the sash there is an air gap, the outlet of which from the outside of the system in cross section view is closer to the sash than its outlet from the inside of the system, whereby the plastic moulding is mounted through clicking or sliding into guides formed by corresponding projections at the frame surface from the side facing the sash in a closed position of the system, and the width of the air gap is from 2.5 to 4 mm, at the edge facing the sash the external profile of the frame is provided with form-fitted external rebate gaskets, by means of which it sealingly engages the external profile of the sash in a closed position of the system.