Efficacy of Water Efficiency Retrofitting (2009)

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This reports evaluates the data from a home audit trial carried out for United Utilities in 2006-2007 to better understand the efficacy of water efficiency retrofitting. 4,642 domestic properties in Warrington were sent an invitation. 393 households took part in the audit and received a ‘water savers pack’, which included a basic shower timer and information on saving water. The data analysis showed that household dynamics, socio-demographic factors and the type of house account for 50% of overall household consumption and 41% on the per capita consumption. The installed devices reduced consumption, with low-flow showerheads being most impactful. 

Supervisor: Dr. Sarah Bell Felipe Doria & Jerome Teo

Dept. Civil, Environmental & Geomatic Engineering

Abstract

Demand management measures aim to increase the efficiency of water usage by using better appliances and changing people’s behaviour. Very little is known about how water appliances influence water use and savings, and water behaviour itself is a complex sociological issue. This research project aims to investigate the efficacy of water efficiency retrofitting. Several statistical analyses such as ANOVA, correlation tests and multiple regression were carried out on the dataset made available to us from the United Utilities Home Audit Project in 2008. Regression models show that household dynamics, socio-demographic factors and the type of house account for 50% of overall household consumption and 41% on the per capita consumption. The results also show that the retrofitted appliances in the Home Audit Project were successful in reducing consumption. Low flow showerhead induces the most savings out of the three appliances retrofitted with 34.9 litres/household/day of savings. Retrofitting more than one type of appliances also saves more water than retrofitting just one type. Respondents who declared that they behaved in a water efficient manner and who changed their use showed a higher percentage of savings compared to those who admitted they did not. According to the regression models, household dynamics plays a crucial role in controlling household behaviour however, it can be compensated to a degree by efficient appliances. The results imply that demand management measures should not just focus on one area. In fact measures combining water efficient technologies and behavioural change are more effective. Limited literature is available on the relationship between household dynamics and behaviour, however our results are consistent with a similar study carried out in Melbourne (Aiken, 1994). House type and design are also significant in the regression model; suggesting future housing development should consider their design impact on the household’s water consumption and even energy consumption for that matter.