What is the Difference Between Dampers and Louvres?

Dampers and Louvres are both very important parts of the wider HVAC system. Whilst the two can look similar to the untrained eye, they do separate (but equally important) jobs.

What is a Damper?

A Damper is a valve that stops or regulates the flow of air inside a duct . There are a number of different types of Damper, each for specific uses. Fire Dampers, as we've discussed in our knowedge hub article about fire dampers, impede the spread of fire and smoke in the event of a fire. Volume Control Dampers help to manage the flow of air in a building as part of the HVAC system. 

Non return Dampers are opened by airflow, and closed by gravity, and are seen in both commercial and residential properties, these Dampers are used to permit air to flow in one direction, but not the other, therefore minimising heat loss from within a building when a system is inactive. Non-Return Dampers if set up correctly have no need for a motor, or manual input.

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True Volume Control Dampers are used for balancing or throttling throughflows, and can be either motorised or manual. Examples of True Volume Control Dampers can be found here S900B, S800B - an offshoot of this type of Damper is a Shut Off Damper that offers a tighter seal in a closed position, these can also be made to be manual or motorised. Examples of Shut Off Dampers can be found on our site, S900C and S800C.

Unlike Fire Dampers, which are almost always made of steel in UK Volume Control Dampers, Non Return Dampers and Shut Off Dampers can be found in a much wider range of materials, such as aluminum and uPVC.

Motorised Dampers are most often electrical, but can also be pneumatic. Electrical motors are available with a range of features to tailor the specific use of a Damper. Modulation as an example can allow control of positions between open and closed going beyond a simple shut off or isolation and enables precise control of the flow rate. Motorised Dampers can also be automated to be controlled by thermostats as part of a larger HVAC system. Spring Return Dampers can be used to ensure the blades return to a fail position in an instance of loss of power, or hydraulic pressure.

For more detailed information on specific types of Dampers, please look to our Knowledge Hub for articles on further applications and subtypes.

What are Louvres?

Louvres, on the other hand, are positioned on the exterior of the building to allow fresh air through and protect the HVAC system against water, dirt and debris ingress, such as rain and leaves. Traditionally, they sit on exhausts or air intakes and have fixed blades which do not close. This means that, if air shut off is required, a secondary damper is required. For example, HVC’s NCA S800C – Heavy duty shut-off

Differences Between Dampers and Louvres

  • Louvres are designed to prevent water, dirt and debris ingress; dampers are designed to manage airflow and impede the spread of fire and smoke (in the case of a Fire Damper).

  • Whether controlled by gravity or motor, the blades on a damper can open or close depending on the requirements. The blades on a louvre are stationary.

What is the Difference Between Dampers and Louvres?