Comparing Apples & Oranges - A Life Cycle Perspective on Energy Requirements in Swedish & British Columbian Building Codes

Abstract: “Comparing Apples & Oranges – A Life Cycle Perspective on the Energy Requirements in Swedish and British Columbian Building Codes” The requirements to decrease the energy use in a building vary in the building codes. “British Columbia Building Code” (BCBC) prescribes a nominal thermal resistance of insulation, while “Boverket’s Building Regulations” (BBR) requires an annual specific energy use for the whole building. A type-house of wood-frame construction complying with BCBC proved to have greater momentary heat losses and a greater average heat transfer coefficient than a type-house of wood frame construction complying with BBR. Further, energy simulations showed that the type-house complying with BCBC did not comply with specific energy use requirement in BBR. The life cycle primary energy use takes into account all stages and all upstream losses during a building’s life cycle. The life cycle perspective takes into account site conditions such as climate and infrastructure. The type-house complying with BCBC proved to use 31-38% more primary energy. The occupancy state proved to use 79-91% of the buildings’ total primary energy. The life cycle perspective can also take into account the greenhouse gas (GHG) emission caused by a building throughout its life cycle. The GHG emissions proved to be strongly dependent on primary energy use. The type-house complying with BCBC emitted 18-42% more GHG than the type-house complying with BBR. GHG emissions occurred predominantly during the occupancy state. BBR takes into account the functionality of the whole building, while BCBC is prescriptive regarding each building assembly. The comprehensive approach towards the building as a system in BBR is according to us a more effective way to decrease the energy use in a single family house.