Water and Energy Efficient Showers Project Report (2007)

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Authors: Richard Critchley, United Utilities and Dr David Phipps, Liverpool John Moores University

This report summarises the findings of an interdisciplinary study, which examined the factors influencing water use of domestic showering. Sponsored by United Utilities, it analysed the physical performance of 20 showerheads or flow restrictors through laboratory work, customer experiences associated with installations of water-saving devices in 18 homes, and water-related energy use through a comparison of shower and bath tube performance. The findings were used to identify and reinforce potential strategies to encourage efficient use of water and energy of showers in homes.

EXECUTIVE SUMMARY

This report describes an interdisciplinary research study of factors affecting water use in domestic showering. The study was sponsored by United Utilities (UU) and undertaken by Liverpool John Moores University (LJMU). The study has investigated showers in terms of both key physical performance criteria and customer satisfaction. The findings have been used to identify and reinforce potential strategies to encourage efficient use of water and energy by showers in homes.

The study has confirmed the major challenge for the UK to implement actions that will influence water use in showers in order to minimise the potential for major increases in water and energy use in the future. The current trend is for a rapidly increasing number of customers to own showers that provide high flow-rate, which together with high frequency of use, results in water and energy use by showers often being greater than for baths. Water use for showers is currently projected to double over the next 20 years.

Shower types

Water use by showers and the appropriate strategies to influence water use vary according to the type of shower.

Electric showers (46% of installed showers) have typical flow-rates of 3 to 8 l/min. The flows are inherently low and any modification to the showerhead or flow characteristics could damage the heating unit.

Mixer showers without pumps (38% of installed showers) have typical flow-rates of 5 to 15 l/min. Pumped showers (16% of installed showers) have typical flow-rates of 10 to over 20 l/min. The fitting of a flow restrictor or regulator, or change of showerhead can be used to reduce the flow of a mixer or pumped shower.

Customer and stakeholder views

Focus groups organised by LJMU found that customers want showers to provide good water flow, at the right temperature, in order to wash and also enjoy the experience of showering. It is perceived as important to have enough water running over the body in order to keep warm in the shower. There is a growing trend toward daily or twice daily showering because of the ease of taking a shower.

There is increasing recognition in the Water Industry and amongst environmental groups of the need to conserve water, including reducing water used by showers, to help protect the environment.