Different Types of Ventilation Ducting Explained
Different Types of Ventilation Ducting Explained
Choosing the correct ventilation ducting is essential for efficient airflow, low noise levels and reliable system performance. The best option depends on the ventilation system, available installation space and whether the ductwork requires additional thermal or acoustic protection.
Below are the main types of ducting available and where each is commonly used.
Semi-Rigid Radial Ducting
Semi-rigid radial ducting is widely used with whole-house MVHR and MEV systems. Individual lengths of duct run from a central distribution box to each room valve, creating a straightforward system with fewer connections along each route.
It is flexible enough to route through floors, ceilings and service spaces while remaining more structured than standard flexible ducting. Its smooth internal surface and limited number of joints also help support efficient airflow and airtight installation.
Best suited to: New builds, renovations, MVHR systems and MEV systems.
Rigid PVC Ducting
Rigid PVC ducting is a practical option for domestic ventilation and extractor fan installations. It is available in both round and rectangular profiles, making it suitable for walls, ceilings, cupboards and other restricted spaces.
Because it maintains its shape, rigid ducting can provide a direct airflow route with less resistance than poorly installed flexible ducting. The fittings can also be used to create bends, branches and transitions throughout the system.
Best suited to: Bathroom fans, kitchen extraction, MEV installations and shorter domestic duct runs.
Metal Ducting
Metal ductwork provides a strong and durable solution for larger domestic, commercial and exposed installations. It is available in a range of diameters with bends, connectors, reducers and other fittings.
Metal ducting is often selected where higher airflow rates, longer duct runs or a more robust installation are required.
Best suited to: Commercial ventilation, larger systems, plant rooms and exposed ductwork.
Flexible Ducting
Flexible ducting is useful when connecting fans, air valves and other components where rigid ducting would be difficult to install. It can be routed around obstacles and is available in several common ventilation sizes.
However, flexible ducting should normally be kept as short and straight as possible. Excessive bends or compressed sections can restrict airflow and reduce system performance.
Best suited to: Short final connections and installations with limited space.
Insulated Ducting
Insulated ducting contains a layer of thermal insulation around the air path. It helps reduce heat transfer and lowers the risk of condensation when ductwork passes through cold spaces such as lofts, garages or unheated roof areas.
Common options include 100mm insulated ducting, 125mm insulated ducting and larger sizes for MVHR and extractor systems. Pre-insulated thermal ductwork can also be used for the external intake and exhaust connections of an MVHR unit.
Best suited to: Cold lofts, external air connections and areas where condensation or heat loss may be a concern.
Acoustic and Sound-Reducing Ducting
Ventilation systems can transfer fan noise and sound between rooms if acoustic performance is not considered during the design.
Acoustic flex duct, acoustic insulation and duct silencers—also known as ventilation silencers or attenuators—can help reduce noise travelling through the ductwork. A duct silencer is commonly installed near the ventilation unit or before room connections to create a quieter system.
Although these products are sometimes described as soundproof ducting, no ductwork system is completely soundproof. Correct duct sizing, suitable fan speeds and careful installation are also important for controlling noise.
Best suited to: MVHR systems, bedrooms, home offices and noise-sensitive installations.
BPC Ventilation supplies semi-rigid, rigid PVC, metal, flexible and thermal ductwork alongside insulation and ducting silencers for domestic and commercial projects.
Which Type of Ducting Should You Choose?
The correct ducting depends on:
- The type of ventilation system.
- Required airflow rates.
- Duct length and available space.
- Whether the duct passes through cold areas.
- The required noise level.
- The number of bends and connections.
Many projects use a combination of products. An MVHR installation, for example, may use semi-rigid radial ducting for room connections, insulated thermal ducting for the external connections and duct silencers to reduce system noise.
Ventilation Ducting Comparison
| Ducting type | Best used for | Main benefit | Key consideration |
|---|---|---|---|
| Semi-rigid radial ducting | MVHR and MEV systems | Airtight, organised room-by-room duct runs | Requires a distribution box and suitable installation space |
| Rigid PVC ducting | Extractor fans and domestic ventilation | Strong, smooth and suitable for direct airflow routes | Correct bends and fittings are needed |
| Metal ducting | Larger domestic and commercial systems | Durable and suitable for higher airflow rates | May require additional acoustic or thermal insulation |
| Flexible ducting | Short connections in restricted spaces | Easy to route around obstacles | Should be kept short and fully extended |
| Insulated ducting | Lofts, garages and external MVHR connections | Helps reduce heat loss and condensation risk | Insulation must remain continuous and properly sealed |
| Acoustic ducting and silencers | Bedrooms and noise-sensitive installations | Helps reduce fan and airflow noise | Works best alongside correct duct sizing and system design |
Get Help Planning Your Ventilation System
BPC Ventilation offers two ways to help you plan and price your system.
Instant Quote Tool
The Instant Quote Tool is suitable for standard MVHR and MEV projects at an early planning or budgeting stage. Enter your property details to receive a basic airflow calculation, suggested system, material list and estimated kit price.
Free Design and Estimate Service
For a more tailored solution, send your house plans to the BPC Ventilation design team. The team can review the property and prepare a free estimate and layout guide based on the requirements of your project. This is recommended for larger homes, unusual layouts and projects requiring a detailed ductwork design.
Choose the right ducting from the beginning to create a ventilation system that is efficient, quiet and suited to your property.
