Designing the user experience of a spatiotemporal automated home heating system: a holistic design and implementation process

This research explores technological interventions to reduce energy use in the domestic sector, a notable contributor to the global energy footprint. In the UK elevated challenges associated with renovating an outdated, poorly performing housing stock render a search for alternatives to provide immediate energy saving at low cost. To solve this problem, this thesis takes a holistic design approach to designing and implementing a spatiotemporal heating solution, and aims to investigate experiences of comfort, thermal comfort concepts for automated home heating, users’ interactions and experiences of living with such a system in context, and the underlying utility of quasi-autonomous spatiotemporal home heating. The mixed-methods research process was employed to explore and answer four questions: 1) what is the context within which these home heating interfaces are used, 2) to what extent can spatiotemporal automated heating minimise energy use while providing thermal comfort, 3) how are different heating strategies experienced by users, and 4) How do visibility of feedback, and intelligibility affect the user experience related to understanding and control? Ideation techniques were used to explore the context within which the designs are used with regard to all factors and actors in play and resulted in a conceptual model of the context to be used as a UX design brief. This developed model used mismatches between users’ expectations and reality to indicate potential thermal comfort behaviour actions and mapped the factors within the home context that affected these mismatches. Potential user inclusion through participatory design provided stakeholder insight and interface designs concepts to be developed into prototypes. The results of a prototype probe study using these prototypes showed that intelligibility should not be an interface design goal in itself, but rather fit in with broader UX design agenda regarding data levels, context specificity, and timescales. Increased autonomy in the system was shown not to directly diminish the experience of control, but rather, control or the lack of originated from an alignment of expectations and reality. A quasi-autonomous spatiotemporal heating system design (including a novel heating control algorithm) was coupled with the design of a smartphone interface and the resultant system was deployed in a low-technology solution demonstrating the potential for academic studies to explore such automated systems in-situ in the intended environment over a long period of time. Assessment of the novel control algorithm in an emulated environment demonstrated its fitness for purpose in reducing the amount of energy required to provide adequate levels of thermal comfort (by a factor of seven compared with EnergyStar recommended settings for programmable thermostats), and that these savings can be increased by including occupants’ thermal preference as a variable in the control algorithm. Field deployment of that algorithm in a low-tech sensor-based heating system assessed the user experience of the automated heating system and its mobile application-based control interface, as well as demonstrated the user thermal comfort experience of two different heating strategies. The results highlighted the potential to utilise the lower energy-use “minimise discomfort” strategy without compromising user thermal comfort in comparison to a “maximise comfort” strategy. Diverse heating system use behaviours were also identified and conceptualised alongside users’ experiences in line with the developed conceptual model. A rich picture analysis of all previous findings was utilised to provide a model of the design space for home automated heating systems, and was used to draw interface design guidelines for a broader range of home automation control interfaces. The work presented here served as important first steps in demonstrating the importance of assessing UX of automated home heating systems in situ over elongated periods of time. Novel contributions of (i) conceptual model of automated systems’ domestic context and thermal comfort behaviours within, (ii) nudging this behaviour by selecting a “minimise discomfort” heating strategy over “maximise comfort”, (iii) using UX to influence user expectations and subsequently energy behaviour, and (iv) inclusion of thermal preference in domestic heating control algorithm were all resultant of examining naturally occurring behaviours in their natural setting. As such, they are important exploratory discoveries and require replication, but provide new research directions that would allow reduction of domestic energy use without compromise

Designing the user experience of a spatiotemporal automated home heating system: a holistic design and implementation process

This research explores technological interventions to reduce energy use in the domestic sector, a notable contributor to the global energy footprint. In the UK elevated challenges associated with renovating an outdated, poorly performing housing stock render a search for alternatives to provide immediate energy saving at low cost. To solve this problem, this thesis takes a holistic design approach to designing and implementing a spatiotemporal heating solution, and aims to investigate experiences of comfort, thermal comfort concepts for automated home heating, users’ interactions and experiences of living with such a system in context, and the underlying utility of quasi-autonomous spatiotemporal home heating. The mixed-methods research process was employed to explore and answer four questions: 1) what is the context within which these home heating interfaces are used, 2) to what extent can spatiotemporal automated heating minimise energy use while providing thermal comfort, 3) how are different heating strategies experienced by users, and 4) How do visibility of feedback, and intelligibility affect the user experience related to understanding and control? Ideation techniques were used to explore the context within which the designs are used with regard to all factors and actors in play and resulted in a conceptual model of the context to be used as a UX design brief. This developed model used mismatches between users’ expectations and reality to indicate potential thermal comfort behaviour actions and mapped the factors within the home context that affected these mismatches. Potential user inclusion through participatory design provided stakeholder insight and interface designs concepts to be developed into prototypes. The results of a prototype probe study using these prototypes showed that intelligibility should not be an interface design goal in itself, but rather fit in with broader UX design agenda regarding data levels, context specificity, and timescales. Increased autonomy in the system was shown not to directly diminish the experience of control, but rather, control or the lack of originated from an alignment of expectations and reality. A quasi-autonomous spatiotemporal heating system design (including a novel heating control algorithm) was coupled with the design of a smartphone interface and the resultant system was deployed in a low-technology solution demonstrating the potential for academic studies to explore such automated systems in-situ in the intended environment over a long period of time. Assessment of the novel control algorithm in an emulated environment demonstrated its fitness for purpose in reducing the amount of energy required to provide adequate levels of thermal comfort (by a factor of seven compared with EnergyStar recommended settings for programmable thermostats), and that these savings can be increased by including occupants’ thermal preference as a variable in the control algorithm. Field deployment of that algorithm in a low-tech sensor-based heating system assessed the user experience of the automated heating system and its mobile application-based control interface, as well as demonstrated the user thermal comfort experience of two different heating strategies. The results highlighted the potential to utilise the lower energy-use “minimise discomfort” strategy without compromising user thermal comfort in comparison to a “maximise comfort” strategy. Diverse heating system use behaviours were also identified and conceptualised alongside users’ experiences in line with the developed conceptual model. A rich picture analysis of all previous findings was utilised to provide a model of the design space for home automated heating systems, and was used to draw interface design guidelines for a broader range of home automation control interfaces. The work presented here served as important first steps in demonstrating the importance of assessing UX of automated home heating systems in situ over elongated periods of time. Novel contributions of (i) conceptual model of automated systems’ domestic context and thermal comfort behaviours within, (ii) nudging this behaviour by selecting a “minimise discomfort” heating strategy over “maximise comfort”, (iii) using UX to influence user expectations and subsequently energy behaviour, and (iv) inclusion of thermal preference in domestic heating control algorithm were all resultant of examining naturally occurring behaviours in their natural setting. As such, they are important exploratory discoveries and require replication, but provide new research directions that would allow reduction of domestic energy use without compromise

A novel spatiotemporal home heating controller design: system emulation and field testing

We have developed a spatiotemporal heating control algorithm for use in homes. This system utilises a combination of relatively low-tech hardware interfaced with electric heating systems and a smartphone interface to this hardware, and a central server that progressively learns users’ room-specific presence profiles and thermal preferences. This paper describes the associated spatiotemporal heating control algorithm, its evaluation utilising the dynamic building performance simulation software EnergyPlus, and a longitudinal deployment of the algorithm controlling a quasi-autonomous spatiotemporal home heating system in three domestic homes. In this we focus on the prediction of occupants’ presence and preferred set-point temperature as well as on the calculation of optimum start time and the utilisation of user-scheduled absences; this for two comfort strategies: to maximise comfort and to minimise discomfort. The former aims to deliver conditions equating to a ‘neutral’ thermal sensation, whereas the latter targets a ‘slightly cool’ sensation with corresponding heating energy savings. Simulation results confirmed that the algorithm functions as intended and that it is capable of reducing energy demand by a factor of seven compared with EnergyStar recommended settings for programmable thermostats. Field study results align with these findings and highlight the possibility to reduce energy under the minimise discomfort strategy without compromising on occupants’ thermal comfort

Living with an autonomous spatiotemporal home heating system: exploration of the user experiences (UX) through a longitudinal technology intervention-based mixed-methods approach

Rising energy demands place pressure on domestic energy consumption, but savings can be delivered through home automation and engaging users with their heating and energy behaviours. The aim of this paper is to explore user experiences (UX) of living with an automated heating system regarding experiences of control, understanding of the system, emerging thermal behaviours, and interactions with the system as this area is not sufficiently researched in the existing homes setting through extended deployment. We present a longitudinal deployment of a quasi-autonomous spatiotemporal home heating system in three homes. Users were provided with a smartphone control application linked to a self-learning heating algorithm. Rich qualitative and quantitative data presented here enabled a holistic exploration of UX. The paper's contribution focuses on highlighting key aspects of UX living with an automated heating systems including (i) adoption of the control interface into the social context, (ii) how users' vigilance in maintaining preferred conditions prevailed as a better indicator of system over-ride than gross deviation from thermal comfort, (iii) limited but motivated proactivity in system-initiated communications as best strategy for soliciting user feedback when inference fails, and (iv) two main motivations for interacting with the interface – managing irregularities when absent from the house and maintaining immediate comfort, latter compromising of a checking behaviour that can transit to a system state alteration behaviour depending on mismatches. We conclude by highlighting the complex socio-technical context in which thermal decisions are made in a situated action manner, and by calling for a more holistic, UX-focused approach in the design of automated home systems involving user experiences