The life cycle impact of refurbishment packages on residential buildings with different initial thermal conditions

Existing buildings constitute a large portion of the UK’s housing stock. Refurbishment of existing buildings can, therefore, have an important role in achieving the UK government’s CO₂ reduction targets. While building regulations and rating frameworks mainly focus on the improvements of the operational performance of buildings, Life Cycle Analysis is considered to be a more appropriate framework to account for long–term CO₂ savings. This study evaluates a range of retrofit approaches (simple, medium, and deep), in terms of Life Cycle Carbon Footprint applied on a terraced house—one of the most common housing archetypes in London. The initial state of the original building has also been examined assuming three initial states (never refurbished, refurbished in compliance with the 1976 and with the 2000 building regulations). Results showed that for all initial state scenarios, deep retrofit achieved the lowest life cycle carbon emissions, in absolute figures, compared to the simple and medium retrofits. Simple retrofit packages, on the other hand, achieved quick and significant improvements, especially in buildings with poor initial thermal conditions. The study also indicated that retrofit packages applied on highly efficient building fabrics result in longer carbon payback time periods. The study recommends establishing a ‘staggered’ retrofitting approach, which pushes for ‘older building first’ and ‘simple retrofit packages first’, as these gain quick CO₂ savings. Deep retrofit packages and treatment of relatively new buildings should be implemented at a later stage, to push buildings further to Zero–Carbon target.