Noise protection and housing development

Conflicting objectives between noise protection and denser development

There is a lack of new housing supply in many regions of Switzerland and an increasing housing shortage in larger cities and their agglomerations. With the growing population and the increasing demand for living space per person, available zoned land for new residential construction is becoming scarcer. For this reason, centrally located, well accessible sites in particular should be developed more densely.

However, this denser development is somewhat at odds with the current noise protection regulations for residential buildings. Conflicting objectives arise because the aim is to achieve more housing in urban locations, but noise pollution is often very high in those areas.

Restrictive noise protection regulations often have a negative impact on the cityscape and cause high costs of construction. Instead of further regulations, incentives for innovation in the planning sector could be created.

Which residential spaces are considered sensitive to noise?

The noise abatement ordinance (Lärmschutzverordnung LSV) distinguishes between relevant noise-sensitive rooms in homes and those in businesses. In residential units, all rooms are defined as noise-sensitive with the exception of kitchens without a living area, bathrooms, corridors and storage rooms. This means that in a residential unit, the living room and all bedrooms are classified as relevantly noise-sensitive.

The ventilation window practice

Until 2016, noise-sensitive rooms in an apartment could be ventilated via a so-called "ventilation window" (Lüftungsfenster). The "ventilation window" was the main point for measuring noise immission, whereby the noise was measured with the window open.

The ventilation window practice of the Swiss Association of Cities (Schweizerischer Städteverband) states that every noise-sensitive room in a residential unit must have a window that complies with the immission limit values. In general, this means that residential construction is permitted if the rear of a building faces away from the noise and is quiet.

What has the 2016 federal supreme court ruling changed?

In 2016, the Swiss federal supreme court ruled in a case in the canton of Aargau that the previous ventilation window practice was not permissible. As a result of the stricter interpretation of noise protection legislation, the immission limit values must now be complied with at all windows in noise-sensitive rooms. This court ruling meant that thousands of planned apartments were no longer eligible for approval under the noise abatement ordinance.

Since then, it is no longer possible to orient living rooms and bedrooms towards noisy locations without an exemption permit, despite controlled ventilation. Because an exemption permit is required in practice, this creates an uncertain legal situation and higher planning costs. The risk of objections also increases.

The legal framework for noise protection

The noise protection ordinance (Lärmschutzverordnung LSV) of December 15, 1986 is the most important regulation in the area of noise protection for residential construction. The LSV is an implementing regulation for the environmental protection act (Umweltschutzgesetz USG) of 7 October 1983. The LSV is hierarchically subordinate to the USG and the regulations in the LSV require a basis in the USG, as they merely represent a concretization of the respective provisions.

How will the legal framework be changed?

Due to the shortage of housing in areas with elevated noise immissions, high-density development is to be facilitated. The most recent proposals in parliament deal with the question of the circumstances under which housing may be built in locations where the noise imission limits are exceeded.

The proposal made by the Swiss Council of States (Ständerat) in December 2023 stipulated that the requirements do not have to be met at any window if the housing unit has mechanical ventilation. Residential buildings should therefore be allowed if the noise-sensitive rooms are artificially ventilated and do not rely on ventilation via a window. Mechanical ventilation systems are not always suitable and lead to higher costs for construction and maintenance.

In March 2024, the Swiss National Council (Nationalrat) opted for a middle ground when discussing amendments to the environmental protection act, which provides for a balance between denser development and noise protection.

Dwelling units should be permitted in noisy locations under the following conditions: At least one noise-sensitive room in each residential unit has a window that complies with the limit values. The other rooms must have mechanical ventilation or there must be a privately usable outdoor space that complies with the noise limits.

As an alternative, it should be possible to build apartments in which at least half of the noise-sensitive rooms have a window that complies with the immission limit values. In addition, the minimum protection under Article 21 of the USG must be tightened in an appropriate and economically proportionate manner.

The National Council and Council of States still must resolve differences regarding the planned amendment to the environmental protection act, but a relaxation of the handling of noise protection in residential development appears to be on the horizon. However, a referendum against the bill has already been announced.