Some Minergie buildings consume more energy than planned
In buildings according to the Minergie and Minergie-P standards, the planning values for energy consumption are usually undercut. Exceptions: administrative buildings and fossil-fuel heated apartment buildings. These are the results of a study by the SFOE.
Evaluations of energy consumption by the Swiss Federal Office of Energy (SFOE) show that the planning values for fossil-fuel-heated, Minergie-certified apartment buildings and administrative buildings are sometimes significantly exceeded during operation. In the case of multi-family houses and administrative buildings according to the statutory building standard, even those with heat pumps sometimes significantly exceed the planning value.
In contrast, the calculated energy demand for all Minergie standards for single-family houses is undercut. The planning values for conversions and Minergie-P new buildings are undercut or complied with, depending on the building category.
Multiple reasons for exceeding the values
The reasons for exceeding the design values in multi-family houses and administrative buildings are manifold, and the study does not provide any reliable findings. According to the Minergie association, which analyzed the study, the main factors influencing consumption seem to be user behavior, occupancy density and suboptimal operation of building services.
Since the number of occupants or employees in a building is hardly known at the time of Minergie certification, the calculation method is based on proven average values defined in SIA standards. The assumptions regarding the average occupancy of the buildings and the room temperatures are particularly sensitive here. Especially in the case of the particularly energy-efficient Minergie buildings, an increase in room temperature from 20°C to 22°C, for example, causes considerable additional energy consumption, according to Minergie.
Minergie is currently revising the Minergie, Minergie-P and Minergie-A building standards; according to the association, significant innovations are expected at the beginning of 2017. Products for intensified quality assurance in the construction phase (MQS) and operational optimization are also being developed. (ah)
