Abstract
Buildings are a major contributor to global energy consumption and greenhouse gas emissions, making them central to achieving sustainability targets such as Europe’s goal of net-zero emissions by 2050. While new developments play a role, the existing building stock – including heritage-protected buildings – requires urgent attention, as most buildings will remain in use well beyond current policy timeframes.
Heritage protected buildings pose unique challenges for energy retrofitting due to regulatory exceptions, lack of integrated services, and other local constraints. These buildings are often older and among the worst-performing in terms of energy efficiency, yet they frequently represent a significant portion of the building stock – locally in Trondheim, up to 10%.
This thesis investigates:
- The state of the art in multi-building energy retrofitting,
- The establishment of representative heritage case studies,
- The modelling and calibration of building energy models, and
- The retrofitting potential of the Central Buildings on the Gløshaugen campus at NTNU in Trondheim, used as a case study.
The case study buildings are publicly owned, non-residential, and locally heritage protected. Their construction period, primary construction material, and typology also make them representative of similar heritage-protected educational buildings in cold climates. This makes them suitable as a representative case study, with transferable lessons to improve future retrofitting efforts.
The PhD study focused on passive retrofitting measures – those that do not rely on active energy systems. Passive measures are particularly relevant for heating consumption in cold climates and are significantly affected by heritage restrictions related to the building envelope, which demand nuanced approaches. All measures and packages tested were carefully coordinated with local heritage authorities, offering a more balanced approach to improving energy performance while respecting conservation requirements.
Ultimately, the research highlights that while heritage protection limits energy retrofitting options, carefully designed passive measures can still yield substantial improvements. However, common retrofitting goals and minimum code requirement are difficult to meet. Scaling past and present retrofitting efforts related to heritage protection buildings – supported by unified policies and better data – could significantly advance sustainable development while preserving cultural heritage.