To respond effectively to the need for a decarbonised economy, the building energy retrofit industry needs to address a number of temporal issues, which affect the calculation of whole life carbon emissions from buildings. This paper contributes to the required discussion by identifying & exploring different temporal considerations and reviewing current approaches, where they exist, to addressing the issues raised. Examples of time-related issues affecting decisions in this domain, include:
• Trade-offs between current and future impacts - an integral part of decision-making processes in many domains, but difficult questions arise as to whether and how to apply discounting to environmental impacts;
• Temporal homogeneity within life cycle inventories - the aggregation of data along the product’s life cycle, with no allowance for timing, of emissions for example, may result in inaccurate estimates of impact and thereby affect the quality of decision-making;
• Reduction of carbon intensity of centralised energy grids - affects the quality of carbon saving predictions from energy retrofits, which heretofore have used a static model of carbon emissions from centralised energy grids;
• The unknown and possibly unknowable longevity of retrofit solutions installed - many of which are new technology, creates problems when attempting to determine their life cycle impacts.