Building type E: Simply constructed. Safely ventilated.

Answer: Yes, it is legally possible – but technically and in terms of liability, it is risky.

Legal freedom:  With the introduction of building type E, it will be possible to explicitly agree in the construction contract that deviations from the “recognized rules of technology” and thus also from the relevant ventilation standards are permitted. If this has been agreed with the client in a legally binding manner, the waiver is no longer automatically considered a construction defect.

The building physics trap: A standard can be deselected, but the laws of nature cannot. Modern buildings are extremely airtight. Without a ventilation concept (and its corresponding implementation), moisture will not be removed. The result is mold growth and poor indoor air quality, regardless of what is stated in the contract.

The liability risk for planners: Architects and planners have an increased duty to provide information for building type E. They must expressly point out to the client the consequences of not installing ventilation that complies with the standard. If damage occurs later because manual window ventilation by the occupants is insufficient, the planner is often still liable if the “suitability for use” of the building is restricted.The liability risk for planners: Architects and planners have an increased duty to provide information for building type E. They must expressly point out to the client the consequences of not installing ventilation that complies with standards. If damage occurs later because manual window ventilation by the occupants is insufficient, the planner is often still liable if the “suitability for use” of the building is restricted.

Our recommendation: Do not ignore the standard without replacement. Take advantage of the freedom offered by building type E to deviate from the often oversized and expensive system technology. Instead, rely on our Type E package: a decentralized solution that ensures the physical protection goal (prevention of moisture damage) without triggering the costs of a comprehensive DIN planning.

Because building type E is intended to reduce costs, but not at the expense of the building fabric and healthy living conditions.

The theoretical assumption that residents will provide the necessary air exchange by manually opening windows almost always fails in practice due to three factors:

The human factor: In order to remove moisture from a modern, airtight building through window ventilation alone, residents would have to ventilate every 2 to 3 hours – even at night and during working hours. This is not feasible in everyday life.

Building protection guarantee: Decentralized ventilation systems operate independently of users. They ensure that minimum ventilation for moisture protection is provided even when residents are on vacation or simply forget to open the window. This reliably prevents mold growth on cold bridges.

Energy efficiency & sound insulation: Opening windows allows expensive heating energy to escape unused in winter and brings street noise into the house. Our decentralized systems in the Type E package ventilate efficiently, keep the heat in the room (heat recovery), and keep the noise out—a comfort gain that pure window ventilation cannot offer.

Conclusion for planners: If you rely exclusively on window ventilation for building type E, you are shifting the risk of structural damage entirely to the behavior of the tenants. With decentralized ventilation, on the other hand, you “automate” building protection. This allows you to build simply (type E), but without the risk of later complaints or renovation costs.

Yes – under one important condition: The technology must be energy efficient, even if the overall building standard is “simpler.”

Although building type E allows for deviations from comfort standards, it does not exempt the building from the legal requirements of the Building Energy Act (GEG). If you would like to take advantage of government promotional loans or grants (e.g., through KfW or BEG), the following rules apply:

Efficiency requirements: In order for decentralized ventilation units to be eligible for funding, they must generally have heat recovery (WRG). Pure exhaust air systems are less frequently funded or receive less funding.

Confirmation by a specialist planner: Even for building type E, KfW and BAFA require the involvement of an energy efficiency expert (EEE) for many programs. This expert must confirm that the selected decentralized solution fits in with the overall energy concept.

Technical bonus: Decentralized systems with heat recovery are often the most cost-effective way to achieve the efficiency house levels required for subsidies (e.g., Efficiency House 40 or 55). While a central system often requires expensive ceiling suspensions and piping, our Type E package allows you to improve your energy balance precisely and within your budget.

Our tip for your budget: Use building type E to save significantly on installation costs (no pipes, fewer trades) and invest part of these savings in highly efficient decentralized devices with heat recovery. This will ensure you receive the maximum subsidy rates while minimizing ongoing heating costs for residents.