Please select your required insulation rating. We currently offer R0.6, R1.0 and R1.5. The higher this figure the thicker the insulation on the ducting will be. As a rule of thumb we generally recommend R.06 ducting for domestic heat transfer applications.
For best airflow, it is recommended to keep the flexible duct tight, as short as possible, avoid sharp turns and keep the duct as round in shape (do not squash it) as much as possible.
Choose the duct size to suit the exhaust fan and for best airflow, use same size or bigger duct than required by the fan.