Does current policy on building energy efficiency reduce a building’s life cycle energy demand?

Building energy efficiency regulations often focus solely on thermal energy demands. Increasing the thermal performance of the building envelope through additional insulation and efficient windows is the typical approach to increasing building thermal energy efficiency. This can result in a significant increase in embodied energy which is currently not considered in building energy regulations. A case study house in Melbourne and Brisbane, Australia is used to investigate the life cycle primary energy repercussions of increasing building energy efficiency levels over 50 years. Embodied and operational energy are quantified using the comprehensive hybrid approach and a dynamic software tool, respectively. Energy efficiency is improved by material or design changes as well as a combination of both. Results show that while increasing the envelope thermal energy performance yields thermal operational energy savings, these can be offset by the additional embodied energy required for additional insulation materials and more efficient windows. The point at which increasing the thermal performance of the envelope does not yield life cycle energy benefits is just above current minimum energy efficiency standards in Australia. In order to reduce a building’s life cycle energy demand, a more comprehensive approach that includes embodied energy and emphasises design changes is needed.