During the combustion process, cold external air flows through the air-carrying tube. Single-walled, non-insulated tubes thus cool down within a short space of time.

The result:

Condensation and/or water droplet formation on the combustion air supply line. This problem is countered by using CB alu insulating flexible tubes (coloured coating).

The elaborately designed CB alu insulating flexible tubes comprise 5 layers:

  • Inner tube 2 layers of alu
  • Insulating shell made of mineral wool
  • Outer tube 2 layers with coloured coating



  • Insulated, flexible supply air tube
  • Flexible airflow
  • High-quality coating
  • Available in grey, black and brown


  • 5-layers
  • Individually packaged
  • Length of inner tube 80 cm, outer tube75 cm
  • Matching rosettes/hose clamps available as accessories
  • Coating heat-resistant up to 200°C

The TR_OL 2012 (technical regulations for stove and air heating construction) states: 

»5.3 Insulation of combustion air lines: to prevent condensation of room humidity, accessible lines must be sufficiently insulated.«

In some countries it must be possible to check and inspect supply air lines.

All alu flexible tubes are packed in premium cardboard boxes to allow, amongst other things, remaining lengths to be repackaged and used for subsequent assembly.

Outside air grill                       Double valve                        LAS-connector                       Connector for separate shaft

Plug-in connector                      Alu flexible tube reducers