To help you find the right duct system and the right size, here we give you a few simple design rules for determining the overall air volumes needed in an apartment or a singlefamily house.
The air volumes for the supply air rooms are specified depending on the planned occupancy, whereby the air volumes should not fall below a minimum volumetric flow of 15 m³/h.
For acoustic reasons, a supply or extract air valve should be specified with a maximum of 40 m³/h. This is unless the valve is explicitly intended for higher flow rates. The air speed in the ducts should be max. 3 m/s. The following tables show the max. volumetric flows for an air speed of 3 m/s for our various duct systems.
You can use these to roughly work out the size and number of ducts and valves you need.
Locating valves
For acoustic reasons, valves should never be installed in the corners of rooms, but instead be at least 1 m away from the wall.
Wherever possible, you should always plan to install supply air valves in the ceiling, or in the wall just below the ceiling. This gives the most effective and comfortable distribution of air in the room. When selecting valves, please consider whether the valve geometry is suitable for the ceiling or the wall.
Extract air valves should also be installed in the ceiling, or close to the ceiling, so that it is always possible to remove the warmest and most humid air from the room. Here, too, the best location is the centre of the room.
If you adhere to these requirements, you will have a system with an external pressure loss of around 60 - 80 Pa. Using the overall air volume and the external pressure loss, you can configure the appropriate unit on our homepage. It is even simpler if you use the specified operating point for our units here in the catalogue: air volume at 50 Pa.