Life cycle cost and carbon footprint of energy efficient refurbishments to 20th century UK school buildings

This study presents a method for assessing energy efficient refurbishment options for schools in the UK. The method accounts for life cycle effects on cost and carbon emissions since refurbished buildings will last for many years.Four schools are identified as representative of school archetypes built in the UK during four distinct periods in the 20th century. The schools are used as a base for simulation of the effects of energy efficient refurbishment of building fabric and heating plant. All possible combinations of the selected measures are simulated. Simulated energy savings are then compared between the four school buildings, demonstrating how physical characteristics of the schools affect the available savings. Simulating combinations of energy efficiency measures allow analysis of interaction effects between measures, and reveals some positive and some negative interactions. A regression model of energy savings in the four schools is also developed.Simulated energy savings are then used as inputs for a life cycle assessment model. Life cycle indicators considered are marginal life cycle cost and marginal life cycle carbon footprint. These metrics are used to rank the energy efficiency measures on net present value and life cycle carbon footprint saving, both individually and in combination with each other.Carbon payback is shorter than financial payback in all scenarios, and all measures and combinations of measures repaid the carbon invested in them. Positive net present value is less common, and frequently depends on air tightness improvements also being achieved.