General planning notes
The aim of good ventilation system planning is to extract cooking vapours out of
the kitchen area as completely and quickly as possible. To help you plan and install
your system correctly, here are a few important notes on system planning from our
ventilation experts.
The planning of a ventilation system is significantly determined by the air requirement
and air output. The air requirement must be contrasted with the corresponding air
output that a ventilation appliance can produce, while taking account of the influence
of all the ventilation components involved.
Air requirement needed:
Please observe the local applicable building regulations when configurating ventilation
solutions. The air output of a complete ventilation system must be designed according
to the air requirement needed. For this, the size of the kitchen and a corresponding
air change rate for the volume of space are often used as the basis for planning. We
recommend this method only if the distance between the ventilation system and the
cooktop is greater than 1.20 m, that is to say, for ceiling ventilation.
– For air extraction operation, the air requirement for the air exchange rate is calcula-
ted using a factor of 10.
– However, the calculation is made using a factor of 12 in kitchens where special
cooking appliances such as the electric grill, Teppan Yaki or wok are used.
– For air recirculation, the air requirement for the air exchange rate is generally
calculated using a factor of 12.
If the distance between the ventilation system and the cooktop is less than 1.20 metres,
the factors listed below must be taken into account to ensure that most of the cooking
vapours are trapped as soon as they rise from the cooktop:
– The size and architecture of the kitchen: As the size of the room increases, the
movements of air in the room also increase and, as a result, the air requirement
becomes greater.
– The cooking appliances: The choice of cooktop is the decisive influencing factor.
Every cooktop produces different types and amounts of cooking vapours. The wider
the cooktop, the higher the output of the ventilation system should be. Above all, the
ventilation system must have a sufficient reserve capacity, if special Vario cooking
appliances, such as a Teppan Yaki, wok or electric grill, are to be installed, because
such appliances can be expected to produce a higher amount of cooking vapours.
We therefore also recommend that these special cooking appliances are installed, if
possible, in the centre of the cooktop configuration and not at the edge.
– The type of ventilation system: Every type of ventilation system has particular cha-
racteristics which influence the air requirement needed. Ventilation systems, such as
downdraft ventilation and table ventilation, are characterised by extracting vapours
directly from the cooktop. As they rise up, the cooking vapours can therefore not
spread as far in the ambient air. In this case, the air output required is usually less
than for those types of ventilation system that are 80 cm or further away from the
cooktop.
– The operation mode: All Gaggenau ventilation systems can be operated both in ex-
haust air mode and air recirculation mode. It should be noted that, in air recirculation
mode, the additional activated charcoal air filter leads to a reduction in air output in
comparison to exhaust air mode. The larger the surface of the activated charcoal air
filter, the more the ventilation system bears comparison in its extraction and noise
behaviour with an exhaust air solution. In air extraction mode, the actual air output
depends not only on the fan output, but also significantly on the duct system.
Important influencing factors on the air output:
– The fans: Gaggenau ventilation systems are equipped with particularly powerful
fans, or they can be combined with correspondingly powerful remote fan units for
exhaust air or air recirculation mode. These fans are also very pressure-stable. They
overcome possible pressure losses caused by a ducting system and work highly
effectively at a low noise level.
– Ducting and installation: To achieve optimum results, the following points should be
observed during installation:
1. Install duct bends with a minimum clearance of 30 cm from the exhaust
air opening.
2. Avoid reductions in cross sections.
3. For duct bends, use bends that are as wide as possible.
4. Only install ducts that have a smooth and flat inner surface.
5. Use exhaust air pipes with a diameter of at least 125 mm.
6. Pay attention to the use of a short ducting paths as possible.
7. Fit wall outlets that have wide fins, wide-meshed grilles and a low back-pressure.
8. Ensure sufficient supply air.
