As part of the project entitled “Innovative Joints for Heat Recovery Ventilation Systems Manufactured Using 3D Printing Technology with Thermally Insulating Composite Photocurable Resins for Building Thermal Renovation in EU Countries”, prototype structural and material solutions were developed to enable the production of a new generation of components for mechanical ventilation systems with heat recovery. The project focused on the use of 3D printing technology and composite photocurable resins modified, among others, with glass and ceramic microspheres exhibiting thermal insulation properties. These materials were used to manufacture ventilation joints with optimized geometries. The developed solutions are intended to reduce aerodynamic flow resistance, improve the energy efficiency of ventilation systems, and minimize the space required for installation. The project results demonstrate the potential of 3D printing technology for manufacturing customized components for heat recovery ventilation systems, adapted to the specific structural conditions of individual buildings. Such solutions may be particularly useful in the thermal renovation of existing buildings, where limited available space makes the installation of conventional ventilation systems difficult. They may therefore contribute to the development of energy-efficient and sustainable construction. The project (Agreement No. DKN/00058/2025) was carried out under the TURBOgrant programme and funded by the Ignacy Łukasiewicz ORLEN Foundation.