For the ultimate in insulation, we recommend our BDX Insulation Collar.
It reduces heat loss by eliminating thermal bridges between the window and your roof structure. Also comes with BFX Underfelt Collar.
Technical details
- Underfelt material: frothed polyethylene, heat transfer group 040.
- Collar material: polypropylene.
- Material thickness: 0.5 mm.
- SD value (water vapour diffusion resistance): 0.03 m.












