Sustainability Report

Gustav Heinemann Comprehensive School achieved a BNB Silver certification, meeting high standards for sustainable construction and operation. BNB (Bewertungssystem Nachhaltiges Bauen) is a German certification system for sustainable buildings.

The school is planned and built according to Passivhaus standards, resulting in a 20 percent energy efficiency, surpassing the stipulated requirements set by the 2016 German Energy Saving Ordinance (EnEV). Primary energy requirements of the building are 57 kWh/m2a.

To achieve its energy efficiency goals, sehw architektur implemented the following measures, along with evaluating their economic efficiency:

• Avoiding energy loss.
• Waste heat recovery.
• Efficient energy generation.
• Use of renewable energy.
• Avoiding unnecessary technology.
• Minimising operational expenses.
• Saving CO2.

The Passivhaus standard allows for the use of residual heat, which can be supplied through the incoming ventilation air that is necessary for the building anyway. The heating load is measured at approximately 10 W/m2K depending on the amount of air needed. The heating energy index is a maximum of 15 kWh/m2a.

Insulated building envelope

The Gustav Heinemann Comprehensive School building envelope is highly insulated. External components were chosen with U-values below 0.15 W/m2K, ensuring minimal heat loss. Glazing or window areas were also carefully selected to have U-values below 0.80, resulting in a total energy transmittance (g) of g ≥ 50%. The combination of a low U-value and high g-value can lead to significant energy savings in the building. This is achieved with a ventilated clinker brick facade and mineral thermal insulation, triple glazing on the windows, and a smart sun protection system that also provides glare protection.

Hybrid ventilation

A hybrid ventilation approach utilises a mix of operable windows and mechanical ventilation. This combination of natural and mechanical ventilation improves comfort levels in extreme weather conditions and delivers efficient CO2 performance. CO2 emissions are measured at 35 percent less compared to a similar building.

The mechanical ventilation system ensures a minimum outside air volume flow of 17 m3/h/person, meeting BNB’s minimum requirements. Additionally, it achieves a heat recovery rate of 80 percent.

PV system

A 2,000-square-meter rooftop photovoltaic system supplies around 250,000 kWh/a of electricity.