Report: Ventilation system 
SINFONIA - Guidelines for nearly zero energy neighbourhoods - Resource database output


New air distribution in apartments 4

Version number: VS VS-02.6
Project phase:    Implemented


The central ventilation unit located in the cold attic is blowing air into the house-distribution system under a constant pressure. The flow control units (connecting each apartment with the house-distribution system) are opening/closing its dampers to get the desired air-flow based on manual flow control of the tenant. The airflow rate is dependent on pressure drop. Thus the fans increase the flow rate in reaction to the opened dampers in order to keep the pre-set pressure drop. Another feature of flow control unit is to keep balance between supply air and return air within the flat. This enhances the airtightness and reduces risk of heat losses through infiltration or exfiltration. When is the airflow adjusted, both inlet and outlet dampers decreasing/increasing the pressure drop proportionally. The flow control unit was placed inside the apartment despite the fact that placement outside in the common staircase would be easier in regards of maintenance. Distribution of air within an apartment is in this variant designed according to cascade-ventilation principle. The fresh air is provided to bedrooms and to a living room. The air is extracted from a kitchen, a bathroom and a toilet. The corridor serves as a transition zone. All ductwork inside the apartment is solely concentrated under the suspended ceiling of the corridor. Thus the living rooms can keep its original height. Inlets and outlets enter rooms simply through the wall, no suspended ceiling is necessary. The number of silencers was reduced from one silencer per supply duct to one central silencer for the complete apartment installation only. This single silencer is actually a junction point created by distribution box itself and coated from inside with scummy “airborne” layer that reduces the sound distribution and crosstalk risk. The ducts are connected to the box in such a way that the ends do not face each other, see attached PDF. In some cases instead of one supply or return semi-rigid duct were used two parallel ducts with a smaller diameter instead, see attached picture. The greater cross-section of a since duct was reduced in order to fit within the suspended ceiling, which was given by width of the flow control unit. Additionally is also reduced the air speed inside each of the ducts. The return-air-diffuser is a simple grill. The supply air diffuser is an end-element of the system, thus is equipped with a dumper for fine adjustment of the air flow. It is used for single-time balancing of housing system and not for frequent adjustments. This final variant VS-02.6 has the same placement of central ventilation unit and building distribution system as the variant VS-01.1 and VS-01.2.

Overall ventilation strategy:


Ventilation unit(s) with heat recovery - standard for airtight buildings


Air distribution within building:

Air distribution concept:

Central (one or more central units for the whole building)

Sketch of air distribution in the building:

Location of the ventilation unit:

Within the attic


Product datasheet:

Link to product datasheet:


Device information:

Number of devices:

More than one per building (central)

Air supply distribution:

Central through staircase

Air extract distribution:

Central through staircase

Global heat recovery rate:

84.0 %

Electricity consumption of the unit:

0.45 W/(m³/h)


Product datasheet of device:

Link to product
datasheet of device:



Distribution within apartment:

Air supply distribution:

Tree distribution with crosstalk sound attenuator

Sketch of air distribution within apartments:

Air extract distribution:

Tree distribution with crosstalk sound attenuator

Air flow control strategy:

Switch with 3 or more levels

Cascade ventilation:

Standard cascade ventilation

Average air exchange rate:

0.6 1/h

Measure for fire protection:



Product datasheet


Link to product datasheet:

SINFONIA - Guidelines for nearly zero energy neighbourhoods - Resource evaluation output

Evaluation on this measure

New air distribution in apartments 4

Overall evaluation of this measure:

The housing companies have carefully evaluated up to 50 detailed questions for this measure.
For better clarity these were broken down to 5 main topics:

General information

Version number: VS VS-02.6
Project phase: Implemented

Get detailed definition of project phases here.

Overall costs of measure

Compatibility with legal affairs

Energy efficiency of measure

Technical feasibility of measure

Design and quality of measure

More detailed evaluation results:

|  poor

  neutral  |  average

top  |


Legal affairs     

Energy efficiency     

Ecological impact     

Construction process     

Technical feasibility     

Architectural design     

Position and orientation     


|  poor

  neutral  |  average

top  |


Personal statement / Global review:

Decisions for implementation: high flexibility; Low cost; easy installation; space-saving

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