Aluminium is one of the most thermally conductive building materials. While this property makes the profile light and durable, if left unprotected it turns into a bridge that carries indoor heat outside in winter. A thermal break is the insulating element placed in the profile section to solve this problem.
The thermal conductivity of aluminium is around 160 W/mK, far higher than that of glass and insulation materials. A non-insulated profile creates a heat path that directly connects the inner and outer surfaces. The consequences are:
A thermally insulated profile consists of two parts: an outer part and an inner part. These two parts are mechanically locked together with polyamide (PA 66 GF 25, i.e. glass-fibre reinforced) strips. The thermal conductivity of polyamide is much lower than that of aluminium. Heat flow slows down significantly at this point, while the profile still works as a single load-bearing element.
The width of the thermal break varies from system to system. For example, in Yılnes systems a 14.8 mm thermal break is used in the RWT55+ door and window system and a 24 mm thermal break in the RESF32 sliding system.
As the width of the thermal break increases, the insulation of the profile generally improves. However, the overall performance of the façade depends on several components working together:
All are expressed in W/m²K, and the lower the value, the better the insulation. Profile calculations are based on EN ISO 10077-2, window and door calculations on EN ISO 10077-1, and curtain wall calculations on EN ISO 12631. When comparing, make sure the values were calculated with the same glass and the same dimensions; Uw values given with different glass combinations cannot be used interchangeably.
In Türkiye, thermal insulation requirements for buildings are assessed under TS 825 and the Regulation on Energy Performance in Buildings; limit values vary according to the degree-day zone of the region. Confirm current values with the relevant legislation.
