IEA - ECBCS - Annex 56 - Cost-Effective Energy & CO2 Emissions Optimization in Building Renovation

In recent years, various standards and regulations for energy consumption in buildings have emerged that specify greatly improved levels of energy efficiency in comparison with earlier requirements. However, these mainly focus on new buildings and do not respond effectively to the numerous technical, functional and economic constraints of the existing stock. It is common that requirements for existing buildings, which are generally targeted at energy efficiency measures, result in expensive processes and complex procedures, seldom accepted by occupants, owners or developers.

But, with an objective of mitigating climate change, renewable energy supply measures can sometimes be at least as cost effective as energy conservation and efficiency measures, if not more so. Therefore, in existing buildings, the most cost-effective renovation solution is often a combination of energy efficiency measures and renewable energy supply measures.

Hence, it is important to investigate where balance point lies between these two types of measures from a cost-benefit perspective. This involves determining how the best performance (in terms of less energy consumption, less carbon dioxide emissions and overall added value achieved by the renovation) would be achieved with the least effort (in terms of investment, interventions in the building and disturbance of occupants). Therefore, a new methodology for energy and carbon dioxide (CO2) emissions optimized building renovation, as a basis for future standards, will be developed to be used by interested private entities and agencies for their renovation decisions, as well as by governmental agencies for the definition of regulations and their implementation.