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DIN 1946-6

DIN 1946-6 – Ventilation of dwellings according to a ventilation concept

Building envelopes in today’s energy-efficient construction are so airtight that window ventilation alone cannot guarantee sufficient air exchange. This can lead to moisture damage, mold infestation, and the accumulation of pollutants (VOCs) in indoor air more easily than in previous years. For this reason, various regulations (standards for ventilation systems) require not only a tight building envelope but also the assurance of a minimum air exchange rate.

Guide topics:

Regulations regarding the air exchange rateaccording to DIN 1946-6

DIN standard 1946-6 outlines solutions for achieving sufficient air exchange in apartments and thus establishes regulations for the ventilation of residential buildings during new construction or renovation. It “applies to natural and mechanical ventilation of apartments and similarly used groups of rooms (units of use) [and] (…) specifies the requirements for the planning, execution, commissioning, operation, and maintenance of the necessary ventilation components (…)” (Source: DIN 1946-6 2009-05). The ventilation system must function independently of the occupants, i.e., even when they are absent. For the ventilation of windowless rooms, however, DIN 18017-3 applies.

The planning and design criteria are intended to ensure that living spaces receive a sufficiently large volume of outside air. This is necessary for the occupants’ health and hygiene when the space is occupied as planned. These requirements apply both to the entire unit and to each individual room.

Relationship between DIN 1946-6and Building Energy Act (GEG)

In addition to the DIN 1946-6 standard, the Building Energy Act (GEG) also plays a central role in the planning of ventilation systems. Both sets of regulations pursue different objectives, but complement each other in practice.
Topic
DIN 1946-6
Building Energy Act (GEG)
Goal
At least user-independent ventilation for moisture protection, for mechanical ventilation systems. Nominal ventilation to ensure health requirements are met during normal operation.
Minimum air exchange rate specified for the entire building
Relation
Implementation aid for fulfilling legal requirements
Legal requirements for energy efficiency
Basis for calculation
Per residential unit, including number of persons, room volume, airtightness
system air exchange
Ventilation levels/air exchange rate
Moisture protection or nominal ventilation + additional levels (reduced, intensive)
0.4 air changes per hour (DIN 18599)
Character
Uses practical, user-oriented parameters
Technical blanket specifications without consideration of user behavior

The ventilation concept according to DIN 1946-6

The requirement of a ventilation concept according to DIN 1946-6 aims to clarify fundamental questions regarding the ventilation of a building or a unit of use. Changes to the building envelope result in changes to the ventilation of the rooms within that building; therefore, a standardized ventilation concept must be developed for every new building as well as for extensive renovations of existing buildings. For existing buildings, a ventilation concept is necessary if more than one-third of the existing windows in single-family and multi-family homes are replaced, or if more than one-third of the roof area in single-family homes is resealed. The planner or contractor must determine how the necessary air exchange can be achieved from a hygiene and building protection perspective. Please feel free to contact us regarding ventilation concepts for single-family homes. The process involves two steps:

Ventilation concept

Determining whether ventilation measures are necessary for the building

Ventilation planning

Suitability of ventilation systems for implementing the necessary measures & selection of a ventilation system

Additional design criteria according to DIN 1946-6

In addition to the general obligation to create a ventilation concept, DIN 1946-6 also specifies exactly how a free ventilation system or mechanical residential ventilation system must be designed. Several practical parameters play a role here that go beyond the standard classification into ventilation levels. The aim of these ventilation measures is to ensure optimal air exchange in all rooms of an apartment or building.

Room volume and number of people

The amount of air required for a ventilation system is not calculated on a flat-rate basis, but rather on a per-dwelling unit basis. The basis for this is the area of the unit and the number of people living in the dwelling. Both factors have a significant influence on the required air exchange rate – especially in terms of humidity and CO₂ levels. In some systems, such as exhaust air systems, the room volume also plays a role, as infiltration must also be taken into account here.

Air tightness and building location

Another important factor in planning a ventilation system is the so-called n50 value, which describes the airtightness of the building envelope. The more airtight the building, the less natural infiltration can be expected – and the greater the need for mechanical ventilation. The building's location, for example in windy or windless regions, also partially influences the necessary design of the residential ventilation system – depending on the ventilation system used.

Consider individual requirements

For precise planning of ventilation systems, it should also be examined whether special requirements exist – for example, for allergy sufferers, in cases of increased noise protection needs (e.g., on busy roads), or in rooms with sensitive hygiene conditions. Such individual factors can influence both the selection of suitable ventilation systems and the precise planning of air volumes.

Ventilation levels according to DIN 1946-6

Air exchange rate according to moisture protection

DIN 1946-6 requires proof of four ventilation levels to ensure sufficient air exchange under different usage conditions. These levels were defined based on experience and studies of buildings. The four ventilation levels are based on characteristic user behavior. According to the standard, four ventilation levels are first distinguished according to their intensity. The different ventilation levels classify the performance of a ventilation system. If the air supply through building leaks is insufficient to ensure adequate ventilation for moisture control, the planner must provide for ventilation measures.

4 ventilation levels (DIN 1946-6)

Ventilation for moisture protection (FL)

Reduced ventilation (RL)

Nominal ventilation (NL)

Intensive ventilation (IL)

Learn more about ventilation levels in our guide: “Why ventilate?”

Guide

Air exchange rate during ventilation

Luftwechsel nach DIN 1946-6
In accordance with the DIN 1946-6 standard and the requirements of the German Energy Saving Ordinance (EnEV) and funding programs, inVENTer offers a calculation tool for the professional design of ventilation systems and is happy to support you with the calculations through a competent service team. Contact us for free consultation support.

According to DIN 1946-6, ventilation for moisture control must be ensured continuously and independently of the occupants, as sufficient, continuous natural ventilation of rooms through wind and thermal activity can no longer be expected in all buildings. This fundamental, user-independent ventilation is intended to prevent mold growth and moisture damage.

Ventilation for moisture control must be ensured independently of the occupants. Therefore, it is not permissible to plan ventilation for moisture control in such a way that occupants have to open windows (window ventilation). In other words, ventilation for moisture control is the minimum standard.

To ensure user-independent ventilation for moisture control, the following factors must be considered:

  • The building’s insulation standard/airtightness – provides information about leaks in the building envelope.
  • The type of building – its size and geometry indicate the expected ventilation requirements.
  • The building’s location – this provides information about wind exposure. The more wind, the greater the natural infiltration.

Air exchange rate after reduced ventilation

Typical use assumes that users are temporarily absent (vacation, during the day). Maximum conceivable moisture inputs are not covered. Drying laundry in apartments is not covered by ventilation for moisture protection, for example.

Air exchange rate according to nominal ventilation

Nominal ventilation is ventilation under normal conditions of use. This covers the ventilation necessary to ensure hygiene and health requirements as well as building protection when users are present during normal operation.

Air exchange rate after intensive ventilation

To reduce peak loads, e.g., during parties, there is also the option of designing the ventilation system for intensive ventilation. However, since peak loads occur relatively rarely, it is advantageous to reduce them using active window ventilation.

Specific ventilation data and device settings

A ventilation concept in accordance with DIN 1946-6 not only provides the required air volumes for each ventilation stage, but also specific information on device settings. This ensures that the required air quality is reliably achieved in practice.

Target and actual values in comparison

For each residential unit, the calculated amount of air required (target) and the amount actually achieved (actual) are specified.

Example from a design:

  • Nominal ventilation: Target 116 m³/h – Actual 121.4 m³/h at 80% device capacity
    This allows you to see at a glance whether the system meets the required values.

Controller settings for different types of use

The concept shows which ventilation level is achieved at which controller setting:

  • 25% device output = humidity protection ventilation
  • 50% = reduced ventilation (e.g. when absent)
  • 80% = nominal ventilation (when the apartment is in full use)

Secure fundingwith the right ventilation concept in accordance with DIN 1946-6

For a ventilation system to be eligible for funding—e.g., via KfW subsidy BEG 261—all of the following criteria must be met:

Planning in accordance with DIN 1946-6 for each residential unit

Achieving an air exchange rate of 0.4 times per hour in accordance with the Building Energy Act (GEG, DIN 18599)

If necessary heat supply efficiency according to funding criteria

Förderung von dezentralen kontrollierten Wohnraumlüftung

What this means:

  • In a tested concept, target and actual values are specified for each ventilation level – e.g., nominal ventilation 116 m³/h, achieved 121.4 m³/h at 80% controller setting.
  • Device settings for different user behaviors are documented (e.g., 25% = moisture protection, 50% = reduced ventilation, 80% = nominal ventilation).

Advantage: With such a concept in conjunction with manufacturer’s certificates, all subsidy criteria are transparently verifiable and you also save on heating costs in the long term thanks to the high heat recovery.

Ventilation conceptsfor non-residential buildings

DIN 1946-6 applies to apartments and units used for similar purposes. However, different legal and normative principles apply to non-residential buildings. Anyone planning such a project must be aware that different regulations and calculation methods apply.

Basis: Instead of ventilation standard DIN 1946-6, workplace guidelines or DIN EN 16798 are often applicable in non-residential buildings.

  • Calculation basis: The workplace guideline aims for an average CO2 content of 1000 ppm. The type of activity and the number of people play a role here! Furthermore, the DIN EN 16798 series of standards can be used for the design of non-residential buildings.
  • Examples of special requirements:
    • Operating rooms with particularly high hygiene standards
    • Schools and daycare centers with increased air exchange requirements for good air quality
    • Sports halls with significantly higher air exchange rates than residential buildings
    • Warehouses or hotels, each with their own guidelines

  • Hygiene requirements: Depending on the use, additional regulations may apply, e.g., for low-germ air in medical areas.

TippPlan the ventilation concept together with the energy consultant

Why

An energy consultant can link the ventilation concept in accordance with DIN 1946-6 directly to the heating load calculation.

Advantage

Heat recovery (HR) is taken into account in the heating load, which reduces the calculated heat demand.

Result

Heating systems are not oversized, which saves investment costs and fuel costs.

Added value

The energy performance certificate provides a much more accurate picture of actual energy consumption.

Conclusionon DIN 1946-6

In today’s energy-efficient buildings, building envelopes are so airtight that normal ventilation practices cannot ensure sufficient air exchange. DIN 1946-6 shows possible solutions for achieving sufficient air exchange in homes. However, this standard contains open and sometimes contradictory passages. For this reason, the design should only be based on standard 1946-6. Planning and interpreting the standard too strictly can often lead to uneconomical solutions. Ventilation planning at inVENTer is carried out in accordance with recognized regulations, namely EnEV, KfW funding conditions, customer requirements, and DIN 1946-6 and DIN 4701-10.

Questions and answers about DIN 1946-6

Heat recovery means that the heat from the exhaust air of a residential ventilation system is used to warm the fresh supply air. This reduces the amount of heating energy lost.

Yes. There are ventilation units with heat recovery (HR) and those without (pure exhaust air units). HR units save heating energy and are mostly used for central rooms in the home. Exhaust air units are often found in bathrooms or WCs, although it is precisely here that valuable heat can be utilized in the form of systems with HR, making these types of units increasingly relevant.

A practical example: Six devices with heat recovery and two exhaust air devices individually achieve up to 87% heat recovery. In the overall system—taking into account all rooms and ventilation measures—the value is 83%.

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