England is projected to face a water supply shortfall of 4 billion litres daily by 2050 due to population growth, water pollution, and increasing climate-driven droughts and flooding. The Environment Act 2021 mandates significant water usage reductions, targeting a decrease to 110 litres per person/day for households and a 15% cut for businesses. Enhancing water efficiency in showers is crucial, given their high water consumption, energy use and associated carbon emissions. Water consumption in 290 showers was covertly monitored for 39 weeks, capturing 86,421 showering events. Increased water pressure was strongly associated with reduced water use - an effect that might be amplified even further by installing timers to inform users of their shower duration.Freshwater availability is under severe pressure(20), worsening with climate change(21,22). England is on the way to suffer from serious water shortages by 2050(23). Also, reducing water demand is needed to achieve net-zero emissions by 2030, committed by the UK water sector(24). Showering is the most (energy and) water-intensive activity in households(25), so nudging users to reduce shower time is an effective intervention leading to energy, water and emissions savings. For instance, a 22% reduction in shower time in households is equivalent to a 5% reduction of the total household energy(26). My PhD proved empirically that using Aguardio, a smart water-saving device that provides real-time feedback, led to a 14% shower reduction in tourism accommodations. Moreover, when persuasive messages were added, shower reduction increased to up to 27%, unveiling the potential to maximise energy and water use efficiency (watch video summary in https://youtu.be/3puOMKnvYeA). My thorough tests have been essential for Aguardio ApS, the Danish start-up behind the technology, to secure £400k private and public investment to redesign and manufacture the new Aguardio market-ready product, available since February 2021. Aguardio allows measuring the effect of behavioural interventions based on actual showering behaviour, providing many opportunities to empirically test psycho-sociological constructs, instead of relying on behavioural intentions, a common shortcoming in the literature. Thus, this fellowship contributes to the largely unexplored fields of how to better persuade consumers to act more pro-environmentally, particularly in fostering water conservation. The fellowship aims, first, to advance knowledge in fostering water conservation by developing behavioural interventions in halls of residence using Aguardio and relevant behavioural change techniques applied in persuasive messages. Second, to disseminate that knowledge by participating in conferences and trade fairs, by publishing the findings in academic and non-academic sources, and by regularly updating the project website (https://showeringsmartly.com/). Third, to escalate the impact by engaging with different sectors (e.g. hospitality, halls of residence, water companies, etc.) encouraging businesses to install Aguardio and develop interventions. And last, to prepare funding bids and develop my academic skills, particularly in advanced quantitative research methods, taking full advantage of the big data that will be available during and after this fellowship. The impact accelerator (IAA) and GCRF fundings awarded after my PhD have facilitated the engagement with the United Nations Environmental Programme, Anglian Water, L'Oréal, Hilton Hotels & Resorts, the Danish Embassy in London, or the University of Surrey halls of residence, reflecting the potential interest that Aguardio draws from different organisations and sectors. The fellowship will allow me to continue providing them with evidence to motivate them to use Aguardio to foster water conservation, so the impact can be escalated. Moreover, through the installation of Aguardio in different organisations, I will have access to big data, offering unprecedented opportunities for future research on real behaviour through behavioural interventions in different contexts, highly increasing the academic, societal and environmental impact that the fellowship on its limited timeframe can create. Ultimately, this fellowship will develop the knowledge about consumers' shower behaviour and ways to optimise communication strategies to foster pro-environmental behaviour, setting up the basis for a holistic understanding of how individuals and organisations engage with water use, currently under-researched.

Through a smart shower device installed in shower cubicles (see https://aguardio.com/), the device continuously measured shower data, specifically water sound, motion detection, temperature, and humidity. Based on these parameters, the device identified showers in real time, recording their duration and showing users the length of their shower time. 290 smart shower devices were installed in 290 shower cubicles in halls of residence, at the University of Surrey. Those showers catered for approximately 1,200 students, who were not aware of being part of the experiment. Our behavioural intervention measured the actual showering duration of a large, randomized sample taken from the population of interest. The study design involved treatment and control conditions. In the treatment condition, the device was working as indicated, informing users of their shower duration. In the control condition, the device display was blinded, so users did not receive feedback on their shower duration. In addition, water flow and water pressure were measured in each of the 290 showers. The study received a favourable ethical opinion from the Research Integrity and Governance Office at the University of Surrey.