Environmental life-cycle of domestic kitchen refurbishment

The refurbishment of domestic kitchens occurs frequently over the lifetime of a building, and often takes place for aesthetic reasons before kitchen components have reached the end of their useful life. This research identifies the consequent significance of the environmental impacts of domestic kitchen refurbishment and develops a model for their evaluation. A pilot study undertaken with staff of the University of Brighton identified the possible occurrence of a high turnover of kitchen refurbishment. The results highlighted that even though the useful life of individual kitchen components is considered to be 20 years, kitchen refurbishments may be undertaken within the first three years of the occupancy of a house. The environmental impacts from kitchen refurbishment have been established through the review of the literature and a case study of real kitchen refurbishment works in Brighton and Hove housing. The literature review revealed the issue of imprecision of published values of embodied energy (EE) for kitchen materials, the variability of which is commonly higher than 40 percent. It was also highlighted the potential relevance of the recurring EE that is associated with a high frequency of kitchen refurbishment. During the case study it was found that the total amount of mixed waste generated in kitchen refurbishment was entirely disposed of into landfill for convenience, although specific waste categories were suitable to be sorted and to undergo a more sustainable waste management. A theoretical model framework has been formulated following the internationally accepted methodology of Life Cycle Assessment (LCA) and, on this basis, a sophisticated LCA kitchen refurbishment model has been computerised to provide a comprehensive and integrated assessment of target environmental impacts such as resource consumption, waste generation, process and transport embodied energy and associated air emissions. The results from the LCA kitchen refurbishment model identified that for one kitchen refurbishment the real use of the major sourcing material was 290 kg of softwood, half of which is wasted during the manufacturing processes. A high proportion of the redundant components (93% of the waste stream) can be re-used or its inherent energy recovered. Further, off-cuts (5%) and packaging (2%) have the potential for recycling. The analysis also established a total life-cycle Embodied Energy (EE) of 8.8 GJ associated with 467 tonnes of CO2 and identified softwood and resin as major contributors. The maximisation of the use of recycled wood in the manufacturing of components for kitchen refurbishment was found to save 450 kg of consumption of virgin softwood and 24% of the CO2 emissions. Scenario analysis has been used to compare the environmental impacts associated with the frequency of refurbishment turnovers of the entire kitchen or individual kitchen components, over a building lifetime of 100 years. The highest environmental impact was associated with the aesthetic scenario which considered the kitchen to be replaced every three years over the building lifetime. The consumption of virgin softwood was 9.6 tonnes, which is eight tonnes more than would be required if the kitchen was refurbished only when it was necessary (functional scenario). The high turnover of kitchen refurbishment was also associated with the generation of 11 tonnes of waste, an embodied energy of 293 GJ and 15 tonnes of associated CO2 emissions, which are equivalent to the impact of ten years of the operational energy consumption of an average UK residential dwelling. This research has established a model which can evaluate and measure the significance of the environmental impacts of kitchen refurbishments within the building's lifetime and has enabled direct evaluation for other refurbishment scenarios.