{"id":{"repo_id":"exeter","oai_identifier":"oai:figshare.com:article/32755293"},"canonical_url":"https://search.dev.ndltd.org/etd/exeter/oai:figshare.com:article/32755293","repository":{"repo_id":"exeter","name":"University of Exeter","base_url":"https://api.figshare.com/v2/oai"},"display":{"title":"Characterising global implications of water and energy consumption for residential showering","abstract":"Global access to clean water and energy resources is essential for sustainable development, however current supplies are under pressure. A major consumer of water and energy in advanced economies is residential properties, which contribute 13% of water and 12% of final energy consumption in Australia. Within residential properties, domestic hot water systems (DHWS) typically consume 20-50% of household water and energy consumption. In many households, the primary demand for hot water is showering. Reducing water and energy demand is therefore important for demand management, with showers a particular target. However, current knowledge of water and energy consumption for showers is fragmented and highly variable, with existing estimates ranging from 10-70% of energy for DHWS. Therefore, the aim of this thesis is to fill critical knowledge gaps in our understanding of water and energy consumption for showering, to reduce uncertainty, and support better analysis, design and policy for residential water and energy efficiency. A literature review of residential water-related energy (WRE) consumption (Chapter 2) identified three key knowledge gaps in current estimates of water and energy consumption of showers: heat loss from DHWS pipes, DHWS configuration, and global coverage of existing studies. To overcome methodological limitations in existing literature and address the aims of the thesis, multiple models and data sources were applied at varied scales and resolutions. Chapter 3 summarises the modelling approaches used in the thesis objectives: 1.A simple model was developed to assess heat loss from DHWS pipes for showers, which was coupled with high-resolution water consumption data and Monte Carlo analysis. The heat loss model was used to predict magnitude and variability in energy and water consumed by showers in the context of Melbourne, Australia. 2.An existing dynamic model was applied to 12 case study households in Melbourne, and Exeter, UK, to assess the effect of DHWS configuration on water and energy consumed by showers. Case study data was drawn from metered and modelled water consumption, surveys, and household audits. 3.A proxy indicator for access to DHWS facilities was developed and applied to global datasets, to generate a high-level global estimate of water and energy consumption for showering and bathing (body washing). The multi-level approach to the modelling analysis enabled deeper understanding of the interactions between local scale sub-systems and the broader global context. Chapter 4 summarises the key results for the individual thesis objectives. Heat loss from DHWS pipes (Objective 1) influences water and energy consumption of showers at the extremes, so is a potential area to reduce water and energy consumption, particularly for specific conditions such as long pipes. In the context of detached dwellings in Melbourne, heat loss from DHWS pipes was predicted to increase water and energy consumption for showers by 4 % (median, interquartile range 2-9%). However, in extreme cases with long DHWS pipes, the modelled heat loss contributed up to 20% of hot water consumption for showering. Different DHWS configurations (Objective 2) can produce trade-offs between magnitude and timing of energy consumption, an important consideration for the global transition to renewables. Households using DHWS with storage tanks consumed more energy than households using instant DHWS, however energy demand for the former was more evenly distributed throughout the day. Heat loss from storage tanks were 14 to 45 % of the energy consumption for showering in applicable households, while peak energy consumption for showers with instant DHWS was four times greater than those with storage tanks. Increasing global access to DHWS facilities (Objective 3) may result in increased global water and energy consumption for body washing. Only 50-65% of the global population was estimated to have access to DHWS facilities in 2020, increasing to 95% in 2050. Corresponding water and energy consumption for body washing was estimated at 300 ± 200 million m3/day and 10 ± 6 TWh/day in 2020 (2 ± 1 % of current global energy consumption), increasing by 50% in 2050 as a result of growing access. Global water and energy consumption associated with body washing could be maintained at estimated 2020 levels, despite rapidly growing access, by reducing average consumption for showering by 50%. However, pooling results from Objective 1, Objective 2, and existing literature demonstrated that physical inefficiencies of DHWS account for only 30% of energy consumption for showering. Efficient behaviours are an alternative, but can be difficult to implement because showers are incredibly important to many people. Therefore, the collective results of this thesis have demonstrated that existing pathways to reduce water and energy consumption of showers may not be sufficient, and innovative solutions are called for. Modern design frameworks emphasise understanding the users of a product or service, so the health and well-being benefits of showering cannot be ignored when designing solutions. Cross-disciplinary efforts to design user-centric solutions in collaboration with fields such as public health and psychology may produce more radical reductions in water and energy consumption for showering than traditional pathways.<p></p>","abstract_html":"Global access to clean water and energy resources is essential for sustainable development, however current supplies are under pressure. A major consumer of water and energy in advanced economies is residential properties, which contribute 13% of water and 12% of final energy consumption in Australia. Within residential properties, domestic hot water systems (DHWS) typically consume 20-50% of household water and energy consumption. In many households, the primary demand for hot water is showering. Reducing water and energy demand is therefore important for demand management, with showers a particular target. However, current knowledge of water and energy consumption for showers is fragmented and highly variable, with existing estimates ranging from 10-70% of energy for DHWS. Therefore, the aim of this thesis is to fill critical knowledge gaps in our understanding of water and energy consumption for showering, to reduce uncertainty, and support better analysis, design and policy for residential water and energy efficiency. A literature review of residential water-related energy (WRE) consumption (Chapter 2) identified three key knowledge gaps in current estimates of water and energy consumption of showers: heat loss from DHWS pipes, DHWS configuration, and global coverage of existing studies. To overcome methodological limitations in existing literature and address the aims of the thesis, multiple models and data sources were applied at varied scales and resolutions. Chapter 3 summarises the modelling approaches used in the thesis objectives: 1.A simple model was developed to assess heat loss from DHWS pipes for showers, which was coupled with high-resolution water consumption data and Monte Carlo analysis. The heat loss model was used to predict magnitude and variability in energy and water consumed by showers in the context of Melbourne, Australia. 2.An existing dynamic model was applied to 12 case study households in Melbourne, and Exeter, UK, to assess the effect of DHWS configuration on water and energy consumed by showers. Case study data was drawn from metered and modelled water consumption, surveys, and household audits. 3.A proxy indicator for access to DHWS facilities was developed and applied to global datasets, to generate a high-level global estimate of water and energy consumption for showering and bathing (body washing). The multi-level approach to the modelling analysis enabled deeper understanding of the interactions between local scale sub-systems and the broader global context. Chapter 4 summarises the key results for the individual thesis objectives. Heat loss from DHWS pipes (Objective 1) influences water and energy consumption of showers at the extremes, so is a potential area to reduce water and energy consumption, particularly for specific conditions such as long pipes. In the context of detached dwellings in Melbourne, heat loss from DHWS pipes was predicted to increase water and energy consumption for showers by 4 % (median, interquartile range 2-9%). However, in extreme cases with long DHWS pipes, the modelled heat loss contributed up to 20% of hot water consumption for showering. Different DHWS configurations (Objective 2) can produce trade-offs between magnitude and timing of energy consumption, an important consideration for the global transition to renewables. Households using DHWS with storage tanks consumed more energy than households using instant DHWS, however energy demand for the former was more evenly distributed throughout the day. Heat loss from storage tanks were 14 to 45 % of the energy consumption for showering in applicable households, while peak energy consumption for showers with instant DHWS was four times greater than those with storage tanks. Increasing global access to DHWS facilities (Objective 3) may result in increased global water and energy consumption for body washing. Only 50-65% of the global population was estimated to have access to DHWS facilities in 2020, increasing to 95% in 2050. Corresponding water and energy consumption for body washing was estimated at 300 ± 200 million m3/day and 10 ± 6 TWh/day in 2020 (2 ± 1 % of current global energy consumption), increasing by 50% in 2050 as a result of growing access. Global water and energy consumption associated with body washing could be maintained at estimated 2020 levels, despite rapidly growing access, by reducing average consumption for showering by 50%. However, pooling results from Objective 1, Objective 2, and existing literature demonstrated that physical inefficiencies of DHWS account for only 30% of energy consumption for showering. Efficient behaviours are an alternative, but can be difficult to implement because showers are incredibly important to many people. Therefore, the collective results of this thesis have demonstrated that existing pathways to reduce water and energy consumption of showers may not be sufficient, and innovative solutions are called for. Modern design frameworks emphasise understanding the users of a product or service, so the health and well-being benefits of showering cannot be ignored when designing solutions. Cross-disciplinary efforts to design user-centric solutions in collaboration with fields such as public health and psychology may produce more radical reductions in water and energy consumption for showering than traditional pathways.&lt;p&gt;&lt;/p&gt;","abstract_has_math":false,"creators":["Rebecca Hall (21052538)"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-06-19T00:00:00Z","date_published":"2026-06-19T00:00:00Z","updated_at":"2026-07-27T19:32:30Z","subjects":["water efficiency","energy efficiency","domestic hot water","modelling"],"languages":[],"rights":["All rights reserved"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["10779/exe.32755293.v1"],"render_values":[{"text":"10779/exe.32755293.v1","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Rebecca Hall (21052538)"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2026-06-19T00:00:00Z"]},{"key":"dc:relation","label":"Dc Relation","values":["https://figshare.com/articles/thesis/Characterising_global_implications_of_water_and_energy_consumption_for_residential_showering/32755293"]},{"key":"dc:type","label":"Dc Type","values":["Text","Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["water efficiency","energy efficiency","domestic hot water","modelling"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["All rights reserved"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10779/exe.32755293.v1"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Global access to clean water and energy resources is essential for sustainable development, however current supplies are under pressure. A major consumer of water and energy in advanced economies is residential properties, which contribute 13% of water and 12% of final energy consumption in Australia. Within residential properties, domestic hot water systems (DHWS) typically consume 20-50% of household water and energy consumption. In many households, the primary demand for hot water is showering. Reducing water and energy demand is therefore important for demand management, with showers a particular target. However, current knowledge of water and energy consumption for showers is fragmented and highly variable, with existing estimates ranging from 10-70% of energy for DHWS. Therefore, the aim of this thesis is to fill critical knowledge gaps in our understanding of water and energy consumption for showering, to reduce uncertainty, and support better analysis, design and policy for residential water and energy efficiency. A literature review of residential water-related energy (WRE) consumption (Chapter 2) identified three key knowledge gaps in current estimates of water and energy consumption of showers: heat loss from DHWS pipes, DHWS configuration, and global coverage of existing studies. To overcome methodological limitations in existing literature and address the aims of the thesis, multiple models and data sources were applied at varied scales and resolutions. Chapter 3 summarises the modelling approaches used in the thesis objectives: 1.A simple model was developed to assess heat loss from DHWS pipes for showers, which was coupled with high-resolution water consumption data and Monte Carlo analysis. The heat loss model was used to predict magnitude and variability in energy and water consumed by showers in the context of Melbourne, Australia. 2.An existing dynamic model was applied to 12 case study households in Melbourne, and Exeter, UK, to assess the effect of DHWS configuration on water and energy consumed by showers. Case study data was drawn from metered and modelled water consumption, surveys, and household audits. 3.A proxy indicator for access to DHWS facilities was developed and applied to global datasets, to generate a high-level global estimate of water and energy consumption for showering and bathing (body washing). The multi-level approach to the modelling analysis enabled deeper understanding of the interactions between local scale sub-systems and the broader global context. Chapter 4 summarises the key results for the individual thesis objectives. Heat loss from DHWS pipes (Objective 1) influences water and energy consumption of showers at the extremes, so is a potential area to reduce water and energy consumption, particularly for specific conditions such as long pipes. In the context of detached dwellings in Melbourne, heat loss from DHWS pipes was predicted to increase water and energy consumption for showers by 4 % (median, interquartile range 2-9%). However, in extreme cases with long DHWS pipes, the modelled heat loss contributed up to 20% of hot water consumption for showering. Different DHWS configurations (Objective 2) can produce trade-offs between magnitude and timing of energy consumption, an important consideration for the global transition to renewables. Households using DHWS with storage tanks consumed more energy than households using instant DHWS, however energy demand for the former was more evenly distributed throughout the day. Heat loss from storage tanks were 14 to 45 % of the energy consumption for showering in applicable households, while peak energy consumption for showers with instant DHWS was four times greater than those with storage tanks. Increasing global access to DHWS facilities (Objective 3) may result in increased global water and energy consumption for body washing. Only 50-65% of the global population was estimated to have access to DHWS facilities in 2020, increasing to 95% in 2050. Corresponding water and energy consumption for body washing was estimated at 300 ± 200 million m3/day and 10 ± 6 TWh/day in 2020 (2 ± 1 % of current global energy consumption), increasing by 50% in 2050 as a result of growing access. Global water and energy consumption associated with body washing could be maintained at estimated 2020 levels, despite rapidly growing access, by reducing average consumption for showering by 50%. However, pooling results from Objective 1, Objective 2, and existing literature demonstrated that physical inefficiencies of DHWS account for only 30% of energy consumption for showering. Efficient behaviours are an alternative, but can be difficult to implement because showers are incredibly important to many people. Therefore, the collective results of this thesis have demonstrated that existing pathways to reduce water and energy consumption of showers may not be sufficient, and innovative solutions are called for. Modern design frameworks emphasise understanding the users of a product or service, so the health and well-being benefits of showering cannot be ignored when designing solutions. Cross-disciplinary efforts to design user-centric solutions in collaboration with fields such as public health and psychology may produce more radical reductions in water and energy consumption for showering than traditional pathways.<p></p>"]},{"key":"dc:title","label":"Title","values":["Characterising global implications of water and energy consumption for residential showering"]}]}],"canonical_facts":{"dc:creator":["Rebecca Hall (21052538)"],"dc:date":["2026-06-19T00:00:00Z"],"dc:description":["Global access to clean water and energy resources is essential for sustainable development, however current supplies are under pressure. A major consumer of water and energy in advanced economies is residential properties, which contribute 13% of water and 12% of final energy consumption in Australia. Within residential properties, domestic hot water systems (DHWS) typically consume 20-50% of household water and energy consumption. In many households, the primary demand for hot water is showering. Reducing water and energy demand is therefore important for demand management, with showers a particular target. However, current knowledge of water and energy consumption for showers is fragmented and highly variable, with existing estimates ranging from 10-70% of energy for DHWS. Therefore, the aim of this thesis is to fill critical knowledge gaps in our understanding of water and energy consumption for showering, to reduce uncertainty, and support better analysis, design and policy for residential water and energy efficiency. A literature review of residential water-related energy (WRE) consumption (Chapter 2) identified three key knowledge gaps in current estimates of water and energy consumption of showers: heat loss from DHWS pipes, DHWS configuration, and global coverage of existing studies. To overcome methodological limitations in existing literature and address the aims of the thesis, multiple models and data sources were applied at varied scales and resolutions. Chapter 3 summarises the modelling approaches used in the thesis objectives: 1.A simple model was developed to assess heat loss from DHWS pipes for showers, which was coupled with high-resolution water consumption data and Monte Carlo analysis. The heat loss model was used to predict magnitude and variability in energy and water consumed by showers in the context of Melbourne, Australia. 2.An existing dynamic model was applied to 12 case study households in Melbourne, and Exeter, UK, to assess the effect of DHWS configuration on water and energy consumed by showers. Case study data was drawn from metered and modelled water consumption, surveys, and household audits. 3.A proxy indicator for access to DHWS facilities was developed and applied to global datasets, to generate a high-level global estimate of water and energy consumption for showering and bathing (body washing). The multi-level approach to the modelling analysis enabled deeper understanding of the interactions between local scale sub-systems and the broader global context. Chapter 4 summarises the key results for the individual thesis objectives. Heat loss from DHWS pipes (Objective 1) influences water and energy consumption of showers at the extremes, so is a potential area to reduce water and energy consumption, particularly for specific conditions such as long pipes. In the context of detached dwellings in Melbourne, heat loss from DHWS pipes was predicted to increase water and energy consumption for showers by 4 % (median, interquartile range 2-9%). However, in extreme cases with long DHWS pipes, the modelled heat loss contributed up to 20% of hot water consumption for showering. Different DHWS configurations (Objective 2) can produce trade-offs between magnitude and timing of energy consumption, an important consideration for the global transition to renewables. Households using DHWS with storage tanks consumed more energy than households using instant DHWS, however energy demand for the former was more evenly distributed throughout the day. Heat loss from storage tanks were 14 to 45 % of the energy consumption for showering in applicable households, while peak energy consumption for showers with instant DHWS was four times greater than those with storage tanks. Increasing global access to DHWS facilities (Objective 3) may result in increased global water and energy consumption for body washing. Only 50-65% of the global population was estimated to have access to DHWS facilities in 2020, increasing to 95% in 2050. Corresponding water and energy consumption for body washing was estimated at 300 ± 200 million m3/day and 10 ± 6 TWh/day in 2020 (2 ± 1 % of current global energy consumption), increasing by 50% in 2050 as a result of growing access. Global water and energy consumption associated with body washing could be maintained at estimated 2020 levels, despite rapidly growing access, by reducing average consumption for showering by 50%. However, pooling results from Objective 1, Objective 2, and existing literature demonstrated that physical inefficiencies of DHWS account for only 30% of energy consumption for showering. Efficient behaviours are an alternative, but can be difficult to implement because showers are incredibly important to many people. Therefore, the collective results of this thesis have demonstrated that existing pathways to reduce water and energy consumption of showers may not be sufficient, and innovative solutions are called for. Modern design frameworks emphasise understanding the users of a product or service, so the health and well-being benefits of showering cannot be ignored when designing solutions. Cross-disciplinary efforts to design user-centric solutions in collaboration with fields such as public health and psychology may produce more radical reductions in water and energy consumption for showering than traditional pathways.<p></p>"],"dc:identifier":["10779/exe.32755293.v1"],"dc:relation":["https://figshare.com/articles/thesis/Characterising_global_implications_of_water_and_energy_consumption_for_residential_showering/32755293"],"dc:rights":["All rights reserved"],"dc:subject":["water efficiency","energy efficiency","domestic hot water","modelling"],"dc:title":["Characterising global implications of water and energy consumption for residential showering"],"dc:type":["Text","Thesis"]},"updated_at":"2026-07-27T19:32:30Z"}