Flexible Ducts

Although many plastic corrugated pipes look similar on the outside, their true quality and longevity are determined by their internal properties and material strength. When choosing ducts for your planned flexible duct system, you must evaluate these technical parameters that will determine your daily comfort:

• Duct diameter (75 mm or 90 mm) - 75 mm pipes are the most popular and versatile choice, transmitting up to 30 m3/h of air per branch. 90 mm ducts are used for very spacious rooms when a higher flow (up to 45 m3/h) is needed, thus avoiding the necessity to run multiple double lines into a single room.
• Inner coating - be sure to look for ducts with certified antibacterial and antistatic coating. Visually, this layer usually stands out with a different color (such as green or blue). This is a crucial hygiene indicator, guaranteeing that your heat recovery unit will deliver truly pure and healthy air.
• Ring (corrugation) strength - high-quality flexible pipes have a strong corrugated structure on the outside that withstands high compressive loads. Because of this feature, they can be safely embedded in concrete slabs – they do not flatten under the weight of building materials and do not lose internal throughput.
• Aerodynamic smoothness - the smoother the inner plastic layer, the lower the pressure drop throughout the ventilation system. This allows your heat recovery unit's motors to work more quietly and use significantly less electricity every day.

Precise airflow planning

When planning a ventilation system, it is vital not to exceed the recommended air velocities in the ducts. If a room needs a flow of 60 m3/h (for example, a large living room with high ceilings), it is always better and quieter to run two 75 mm ducts into one plenum box than to try to "squeeze" the entire air volume through one pipe at high pressure. This way you will avoid any whistling and ensure a quiet environment.