Improving the energy performance of an historic building : A study of the tradeoff between cultural heritage and energy performance

In order to reduce the energy consumption of buildings some degree of alteration usually needs to be done to its shell and construction, which can change the appearance of the building. At the same time buildings often carry materials, details, construction methods, and other historically significant artifacts, that are important to perserve. This often leads to compromises having to be made between improvements to energy performance, and the perservation of the cultural heritage of the building. In this project, a building from the late 1800s in Söderhamn, Sweden, was analyzed to find appropriate energy saving measures while also taking its cultural history into consideration. The simulation software VIP Energy was used to build a model of the house where simulations of different energy saving measures as well as different cases of occupant behaviour could be tested. From these tests, measures were selected and sorted into three packages depending on their level of energy reduction, invasiveness of cultural heritage, and overall complexity. Package A had the lowest energy reduction, but also the lowest invasiveness and complexity of the three. Package C had the highest energy reduction, but with next to no regard for the cultural heritage of the building, nor the complexity of implementing the measures in it. Package B was chosen to contain the measures that according to the authors sucessfully strike a balance between energy effectiveness and the perservation the building’s cultural heritage. The model of the building without measures implemented had a primary energy value of 181kW h/m2, an energy usage of 117 kW h/m2, and a thermal conductivity of 0.504 W/m2K. With package B implemented, the primary energy value was reduced to 54.3 kW h/m2, the energy usage to 32.4 kW h/m2, and the thermal conductivity to 0.247 W/m2K, which makes the building live up to the current standards set by the National Board of Housing, Building and Planning. With proper occupant behaviour, the primary energy value and the energy usage could be further reduced to 24.5 kW h/m2 and 32.4 kW h/m2 respectively. Our results suggest that large energy improvements can be made to buildings similar to this one, and that occupant behaviour is a big uncertainty when energy simulations on buildings are performed