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P.P. de la Barra Luegmayer

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Device type, position, and system cues influencing user preference and acceptance

Journal article (2026) - P. de la Barra, P. Martinez-Alcaraz, E. Brembilla, G. Brager, K. Exss, A. Luna-Navarro
The integration of smart control systems in office buildings can be disruptive when individual preferences and expectations for control interfaces are overlooked. Understanding how human–building interaction influences environmental comfort and acceptance is essential for creating user-centered designs. This study aimed to evaluate the effectiveness of usability testing as an innovative method for assessing building system control interfaces and user interaction with automation. Specifically, we examined user preferences for shading and lighting controls in a controlled office laboratory, varying by “Type of Device” (analog vs. digital), “Position” (wall, desk, or split), and “System Cues” (information richness). In an experimental setting involving 20 participants, we investigated how these factors influence satisfaction and acceptance of automation. Using an adapted Post-Study System Usability Questionnaire (PSSUQ), we evaluated satisfaction with Ease of Use, Reachability, and Information. Findings show that while participants’ initial expectations favored simple analog controls, preferences shifted toward digital, information-rich systems after hands-on interaction. Ordered logistic regression confirmed that Reachability (β=2.317) and Ease of Use (β=1.831) were the strongest predictors of Overall Satisfaction (p<0.001), placing interface position as the primary design characteristic. However, preferences varied by office type: in shared offices, users preferred wall-mounted controls to facilitate shared access and visibility. These insights offer actionable guidance for designing smart control interfaces that enhance user satisfaction, support personal control, and promote greater acceptance of building automation. ...
Building automation and control systems (BACS) are central to energy performance and occupant comfort in non-residential buildings. Comfort is inherently multi-domain, including thermal, visual, acoustic, and air quality requirements. Multi-domain BACS involves frequent trade-offs across domains when conflicting control actions arise, such as providing glare control versus daylight availability. Yet existing occupant-centric control research treats building services in isolation, and prior multi-domain comfort reviews rarely examine how multi-domain demands are integrated into BACS decision logic across services. We conducted a systematic review of 43 studies to examine how multi-domain occupant demands are represented and operationalized in BACS. Across the evidence base, thermal comfort is universal, while visual and air quality are frequently included. Acoustics is rarely addressed due controllability constraints. Most studies remain unimodal in their demand representation, even when multiple domains are in scope. Integrated BACS implementations are therefore largely built on within-domain formulations. Multimodal demand models that encode cross-domain and combined effects are uncommon and are rarely implemented in integrated BACS. Rule-based strategies dominate multi-domain controllers. Optimization-based and learning-based controllers are also used, but they often rely on fixed weights or reward terms that make trade-offs difficult to interpret. In addition, actuator choice is rarely made explicit when multiple services can achieve the same target state. Future research should benchmark unimodal and multimodal demand formulations under comparable control contexts, extend bottom-up multimodal models beyond thermal and air quality into integrated BACS, especially for façade control, and develop transparent, preference-aware policy designs that make priorities and service actions understandable. ...
The integration of smart control systems in office buildings often neglects individual expectations and preferences, especially when occupants do not have personal control over their environment. While existing research has advanced personalized comfort models, simulated energy-use behaviors, and quantitative methods for occupant-centric building design, it often overlooks the critical role of personalized control interfaces. These interfaces are essential for integrating occupants into the operable building systems. This study investigates occupant preferences for personal control after experiencing different building control interfaces for lighting and roller shades in an office environment. Using a usability testing approach, 20 participants were involved in brief interaction sessions to evaluate how interface type (digital vs. analogue), position (wall-mounted vs. desk-mounted), and level of information influence occupants’ satisfaction. Additionally, we explored whether participants’ preferences for indoor environmental quality conditions correspond with their reported satisfaction with building control interfaces. Results show that interface placement significantly influences user preference, beyond ease of access. While participants initially favored analogue controls and manual operation, exposure to digital and automated systems led to greater acceptance, particularly when these systems provided clear information and maintained personal control. These findings underscore the importance of actual experiences with system interfaces in understanding occupant preferences and acceptance with building technologies, which is key for occupant-centered design in building control. ...
Conference paper (2026) - P. de la Barra, M. S. Khanie, A. Luna-Navarro, P. Martinez-Alcaraz, D. Al Assaad, E. M. Barrett, G. Chinazzo, Z. Deng, B. Dong, More Authors
Buildings are striving to be both energy-efficient and occupant-centered. Personalized systems for lighting and dynamic fenestration systems, e.g., switchable glazing, are emerging as a key solution. These systems, called Personalized Environmental Control Systems (PECS), allow individuals to adjust their immediate environment without impacting others. While PECS initially focused on temperature and air quality, this study explores the potential for the luminous environment, introducing the concept of Visual PECS.

Daylighting and lighting controls build on a long history of personalized systems and methods, from prehistoric torches to adjustable desk lamps. They allow for individual control over (day)light spectrum and intensity, catering to personal needs and promoting circadian health and cellular processes (i.e., photobiomodulation). Additionally, they can reduce glare and improve visual comfort, leading to increased productivity and well-being. Despite this long history, studies formulating “personalized environmental control systems” (PECS) in the daylighting and lighting domain are rare. In this paper, we present preliminary results from a comprehensive review, where 31 papers were identified from an initial pool of 5,238. The findings highlighted two key benefits. First, semi-automated PECS offer the highest energy savings, highlighting the importance of understanding the relationship between users and automation. Secondly, PECS provides improved occupant experience since the ability to control their environment empowers occupants, leading to increased comfort and productivity. Overall, PECS have the potential to facilitate individual control over lighting and visual parameters, ultimately enhancing visual comfort and satisfaction as well as beyond-visual well-being. Our research builds upon the ongoing work of IEA EBC - Annex 87, which investigates the energy and environmental benefits of PECS. ...

Interaction Requirements to Enhance Acceptance of Automated Control Strategies

This dissertation investigates how interaction strategies shape occupant responses to automated façades in office buildings, contributing to reducing the gap between predicted and actual performance. Automated façades, such as roller shades, venetian blinds, and switchable glazing, offer potential to reduce energy demand and improve indoor environmental quality. However, their effectiveness is often undermined by misalignment between automated control logic and occupant comfort requirements, leading to dissatisfaction and frequent manual overrides.
Using a mixed-methods approach, the research combines systematic literature reviews, controlled laboratory experiments, and large-scale surveys. The findings show that while automated façades can substantially reduce lighting energy use, their overall performance depends strongly on occupant interaction. Five key factors influence acceptance: personal preferences, environmental conditions, context, façade technology, and control logic. In particular, interaction design, such as how quickly and in what way façade systems adjust, control usability, and information availability, plays a critical role in shaping satisfaction and behavior.
Experimental results demonstrate that disruptive automation increases override actions, whereas systems that are understandable, predictable, and easy to control foster trust and acceptance. Survey data further show that occupants prefer differentiated levels of automation depending on context, building service, and time of day, with a general tendency toward “mixed-control” strategies.
The dissertation frames an “interaction gap,” arguing that energy efficiency and occupant comfort depend on occupant-centered design. It concludes that effective façade strategies must integrate clear communication, low-effort override options, and context-sensitive control.
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Building Automation and Control Systems (BACS) enhance energy efficiency in office buildings but often leave occupants dissatisfied, especially in shared offices with diverse indoor environmental preferences. Personal Comfort Models (PCM) capture individual preferences, yet these models can be difficult to apply in shared environments. This study examines whether a generalized personalized modeling would be necessary, or instead aggregated thermal preferences adequately represent individual needs in shared spaces. By mining the ASHRAE Global Thermal Comfort Database II, we analyzed 11 naturally ventilated office buildings spanning four climate zones, each providing 187 to 568 data points of subjective thermal preferences and concurrent environmental measurements. To capture uncertainties in occupant feedback and monitoring, we developed a Bayesian multinomial logistic framework. We compare an aggregated model (all responses together) with a hierarchical (partial-pooling) model having occupant-specific intercepts, using the No‑U‑Turn Sampler for Hamiltonian Monte Carlo. The Widely Applicable Bayesian Information Criterion confirms that hierarchical approach outperforms the aggregated model in every case. In four of the eleven studies, aggregated air temperature ranges satisfied occupants’ demands within a 95% posterior credible interval. Moreover, in most buildings, these temperature ranges aligned well with the majority of occupant preferences, suggesting that prior knowledge of building conditions or occupant variability might reduce the need for highly customized thermal environment. Future research should explore these findings in conditioned buildings and across other indoor environmental quality domains, where greater variability could exist. ...
This paper explores the challenge of gathering occupant feedback in real office environments, focusing on the difference between continuous versus one-time questionnaire methods. Continuous feedback methods are valuable for understanding occupant needs, but they can lead to disengagement and fatigue over time, while one-time questionnaires usually focus on one moment in time and they cannot capture changes or trends over time.

A Pre-Occupancy Evaluation (PrOE) was conducted in a German office before a design intervention. This study compares the data obtained from the German office in a one-time and a continuous questionnaire to evaluate their respective benefits and limitation in informing required design solutions for a pilot area. Both a one-time online questionnaire and a continuous feedback system (implemented using QR codes) were used to collect data on occupant (dis)satisfaction with the office design.

The results of this research show different perception on occupant’s satisfaction between the two surveys. Both surveys show congruency in the dissatisfaction with open offices without partitions than in shared enclosed offices. The one-time survey highlights a lowest satisfaction with the availability of personal control, while the continuous survey presents lowest satisfaction with the acoustic privacy. ...
Review (2025) - P. de la Barra Luegmayer, E. Brembilla, Alejandro Prieto, Claudio Vásquez, U. Knaack, Alessandra Luna-Navarro
In recent years, several studies have assessed the influence of automated façades on energy savings, IEQ, and occupant satisfaction. However, discrepancies exist between the expected advantages of automated façades predicted in research and the actual benefits observed in real-world tests. To assess how automated façade operation enhances building performance, in particular within office building contexts, this study reviews and analyzes current evidence on the influence of automated façades. In this review, 91 studies were identified presenting evidence of their performance. A total of 34 studies investigated performance in laboratory settings, 23 in real office buildings, and 34 in simulations. Only 13 laboratory studies and 17 real office building studies included human participants. Visual and thermal quality were the main indoor environmental domains investigated, with limited exploration of others. Existing studies show large variability in contextual factors (e.g., type of shading and control) or experimental designs (e.g., different benchmark scenarios), hindering the comparison of results. Consistent evidence shows the potential of automated façades for energy savings, particularly in lighting and cooling demands, which outperform manual control systems. Automated controls are more effective in reducing excessive daylight and glare, while evidence of the impact on thermal and air quality remains limited. Regarding occupant satisfaction, evidence is unclear since, in some cases, occupants prefer manually controlled façades and, in others, automated ones. Further research is suggested on human-centered studies in real office buildings to capture occupant behavior and preferences while exploring solutions that dynamically identify and integrate factors affecting occupant interaction with buildings. ...

Effect of switching speed under overcast sky condition

Smart dynamic building technologies can help to significantly reduce operational energy and carbon emissions. However, human acceptance remains a significant barrier, particularly for switchable glazing used in smart windows. This study examines how users are affected by the speed and direction of transitions in the transparency of fast switchable glazing, specifically dynamic liquid crystal technology under overcast sky. Perceptual and behavioural data including facial action units, were collected through an experimental campaign in a semi-controlled environment where the glazing transparency was transitioned at two rates (1 and 10 s). It was found that user perception remained consistent regardless of transition speed or direction, but override behaviour was influenced by both factors. In the absence of glare, user overrides were primarily driven by the transition direction, with more users reacting to transitions from dark to clear. Faster transition rates led to an increase in user overrides for both transition directions. Unlike those who did not override, users who overrode the automated glazing control strategy had a negative perception of the visual environment and the window control system. Users directed their gaze more towards the glazing when this was transitioning, suggesting possible distractions. Users were clustered based on their background knowledge and reported preferences. These clusters showed a good correlation with the override delay times. However, the agreement with actual behaviour was low, indicating that a larger number of variables and clusters should be tested to predict user behaviour. Nevertheless, clustering users highlighted the importance of considering individual differences for interaction strategies. ...
Conference paper (2025) - P. Martinez-Alcaraz, P. de la Barra, C. P. Andriotis, Y. Wang, A. Luna-Navarro
It is a challenge for traditional building control systems to meet occupants’ needs in shared spaces due to the lack of understanding of individual occupant thermal preferences. This is a barrier to balancing energy efficiency and indoor environmental quality (IEQ). Advanced statistical learning methods offer new solutions towards more energy-efficient and user-centric control logics. In this work, a control logic is proposed to optimise the heating, ventilation and air conditioning (HVAC) operation based on thermal comfort archetype preferences, leveraging the ASHRAE Global Thermal Comfort Database II in conjunction with energy simulations. First, we apply the k-means clustering algorithm to categorize occupants into different archetypes regarding their common feedback on the thermal environment. Then, we fit a Bayesian logistic regression model to predict the thermal comfort preferences of different archetypes based on IEQ data. Finally, we identify two occupant-centric control logics to optimize HVAC operation to meet occupants’ requirements: (i) considering a unified response of thermal comfort in the space, and (ii) ensuring the dynamic optimal setpoint when conflicting occupant archetypes are present. Having compared this control logic with a common rule-based logic, our results demonstrate the potential of occupant-centric controls and the importance of multi-objective metrics in accounting for energy efficiency. ...
Control systems in buildings that prioritise occupant preferences have gained attention recently, intending to enhance the acceptability of automated systems. However, effective human-building interaction strategies remain challenging to design due to the lack of understanding of building occupant preferences. This study aims to identify factors influencing occupant satisfaction with building control systems to provide insights for improvement in interaction strategies. Surveys conducted in buildings located in Riga (Latvia) and Delft (The Netherlands) collected data on satisfaction with indoor environmental quality (IEQ), building controls, productivity, control importance, and social-subjective norms. Analysis categorised respondents into high and low satisfaction clusters and identified significant factors influencing satisfaction with IEQ through non-parametric tests. Logistic regression and coefficient analysis were used to assess the relationship between satisfaction and these factors. Findings suggest factors influencing satisfaction with IEQ, personal control, and automation, underscoring the developed methodology's potential. The identification of these factors informs actions that might enhance Human-Building Interaction (HBI) strategies, emphasising tailored approaches and addressing control system limitations. Further research is necessary to evaluate these strategies and understand how insights into human-building interaction strategies can lead to higher satisfaction levels. ...

Performance Metrics to Evaluate the Ability of Indoor Space and Facade Systems to Connect to Outdoors

Journal article (2025) - Claudio Vásquez, Pedro de la Barra, Renato D’alençon, Camila Da Rocha
Indoor-outdoor visual connectivity studies focus on analyzing view vectors and their spatial distribution, considering the three-dimensional nature of visual perception. Typically, these studies use the observer's position as a focal point from which view vectors radiate outward. However, they often overlook the multiple positions an observer can occupy in space and the various relationships these positions create with the façade system, leading to differing visual connections to the outside environment. Specialized studies that analyze multiple observer positions provide valuable insights by mapping visual connections for each location. However, they tend to lack a singular metric to assess indoor-outdoor visual connectivity as a factor influencing visual performance in relation to the space and façade system.

This article introduces the Visual Connectivity Index (VCI)—a metric designed to evaluate indoor-outdoor visual connectivity. VCI measures the relationship between a façade system and the indoor space it encloses, assessing how uniformly and seamlessly the interior connects to the exterior through the façade system while considering multiple observer positions. VCI contributes to three key areas: (1) It enables the evaluation of a façade system’s impact on visual connectivity and its interaction with enclosed space; (2) It provides a performance-based measure of visual connectivity (3) It facilitates the comparison of alternative design solutions within the framework of architectural design.

By synthesizing the complex phenomenon of indoor-outdoor visual connectivity with the role of the façade in shaping this relationship, Visual Connectivity Index (VCI) presents a novel and valuable approach that has not been previously explored. To demonstrate its application, this study systematically compares the performance of 20 design alternatives across three different façade systems, resulting in a total of 60 iterations. The results indicate that VCI is sensitive to various design options, enabling a thorough evaluation of different architectural design choices. ...

Demonstration of BIM-Integrated IoT Window Signaling System

Conference paper (2025) - Alessandro D’Amico, Federico Fiume, Pedro de la Barra, Alessandra Luna-Navarro
Indoor Environmental Quality (IEQ) plays a crucial role in the health, well-being, and cognitive performance of students in school environments. This study presents the integration of Building Information Modeling (BIM) and Internet of Things (IoT) sensors for real-time IEQ monitoring and dynamic ventilation control. A BIM-integrated window signaling system was developed using visual programming to process real-time sensor data and provide feedback on optimal window operation times. The methodology consisted of five phases: (1) development of a BIM model of the case study and calculation of window opening time, (2) on-site deployment of an IoT sensor system, (3) integration of real-time environmental data into the BIM model, (4) generation of a continuously updated digital twin for IEQ assessment, and (5) comparison between calculated ventilation times and measured environmental parameters. The system was tested in two classrooms of a school in Rome, Italy, where temperature and CO₂ concentration were continuously monitored. The results indicate that the calculated ventilation schedules effectively maintained indoor temperatures within recommended thresholds. However, CO₂ levels frequently exceeded the guide value threshold in one classroom, revealing discrepancies between the expected and actual window opening behaviors of occupants. The study underscores the role of occupant compliance in ventilation effectiveness and demonstrates how BIM can function as a dynamic decision-support tool by integrating real-time environmental data, automated parameter updates, and graphical trend visualization. ...
Journal article (2025) - Dolaana Khovalyg, Mariya P. Bivolarova, Jun Shinoda, Douaa Al-Assaad, Marika Vellei, Karol Bandurski, Pablo Martinez Alcaraz, P. de la Barra Luegmayer, Alessandra Luna-Navarro, More authors...
Advances in environmental technologies have improved indoor environmental quality (IEQ) by creating steady, uniform conditions. However, these often fail to meet individual thermal comfort and air quality needs, prompting a shift toward adaptive, personalized solutions. Personalized Environmental Control Systems (PECS) aim to enhance comfort, air quality, health, and productivity through user-centered designs. This paper systematically reviews 324 journal articles on PECS from 1988-2023, focusing on thermal and indoor air quality (IAQ) domains. PECS are classified by mobility: building-attached, semi-attached, detached, and wearable. The review assesses their impact on thermal comfort, IAQ, health outcomes (e.g., Sick Building Syndrome, heat stress), and human performance (e.g., cognitive function, productivity). Results show that building-detached PECS often improve thermal sensation, comfort, and acceptability, with combined systems yielding better ratings. Personalized ventilation enhances IAQ by delivering clean air directly to the breathing zone, reducing contaminant exposure. Research on PECS effects on health is limited, mainly focusing on short-term, controlled studies. Evidence for benefits on human performance is sparse but promising. Key challenges include inconsistent performance metrics, limited real-world evaluations, and potential publication bias toward positive results. This review highlights the need for standardized evaluation methods, deeper understanding of combined PECS effects, real-world and long-term testing, and clearer quantification of human performance benefits to advance the field. ...
Conference paper (2025) - Alessandra Luna-Navarro, Andrea Welti, Pedro de la Barra, Pablo Martinez-Alcaraz, Matteo Porta
The Smart Readiness Indicator (SRI), introduced by the European Union in 2018, assesses a building’s capacity to accommodate smart-ready services. This evaluation focuses on optimizing energy efficiency, aligning operations with occupant needs, and responding to signals from the grid. Previous studies have evaluated SRI feasibility in various locations and retrofit scenarios, estimating the costs associated with implementing smart technologies in existing European buildings. However, the specific impact of digitizing distinct building services on SRI scores remains unexplored. Particularly, adaptive façade technologies show potential in enhancing overall building performance, being worthy to understand how these services influence the smart readiness rating of buildings. This study investigates the impact of adaptive façade technologies on SRI scores and user satisfaction. A case study of an office building in Delft (The Netherlands) was selected to assess the impact of smart technologies on energy efficiency and comfort. This paper shows preliminary results from the pre-intervention phase, where the SRI was calculated for both the baseline condition and a scenario with the highest possible level of smart services for the building envelope. The results from the SRI methodology showed an increase of approximately 4% in energy efficiency and 15% in terms of energy flexibility. In addition, the SRI predicts similar improvements in user convenience, information, health & well-being, but only 4% in user comfort. This was confirmed by the assessments on user perception and preferences. Users reported to be “slightly satisfied” with several comfort domains. Additionally, several users considered better control of external shadings very important, which was currently reported as very disruptive by users. This preliminary finding shows potential for smart services applied at the façade level to improve user satisfaction if aspects of interaction and convenience are adequately addressed. Post-intervention phase data is now required to confirm these preliminary findings. ...
Visual defects, in particular haze, in glass and façade technologies can significantly impact the aesthetic quality and human experience of daylight and views in buildings. The glass and façade industry increasingly requires methods that can objectively predict and measure the subjective user experience of haze. This is required to appropriately inform the manufacturing process, ensuring optimal functionality and performance, and avoiding material waste and economic losses due to the replacement of defective glazing. Existing methods for measuring haze are not appropriate for assessing large samples, either at manufacturing sites or in-situ. However, haze defects are often only exhibited and visible when glazing is produced in large samples or installed under real luminous conditions. This paper introduces a novel luminance-based method that measures haze by evaluating the halo around a light source that is observed through the glazing. This method is initially tested in a controlled laboratory setting on small glazing samples with varying level of haze. The halo serves as a proxy for haze severity and it is quantified by using luminance-based measurements. In this work, the newly-proposed method is verified by comparing the ranking in haze severity of different samples as performed by means of a standard haze meter and the newly proposed method. Additionally, the paper examines the dependence of this ranking on factors such as camera setup distance and light intensity. It was found that the proposed method was able to effectively ranks samples differing in haze intensity by more than 0.1 orders of magnitude. Positioning the camera closer to the glazing and using higher light intensity yielded more accurate results. However, for haze levels below 1% and differences smaller than 0.1 orders of magnitude, the accuracy is insufficient. To define the expected level of accuracy of methods for haze characterisation in-situ, the sensitivity of the human eye to haze under varying luminous environments and view content needs to be quantified. ...

New evidence from human-centred studies

The performance of the building envelope is crucial for minimizing operational carbon emissions of buildings and maintaining indoor comfort. Contemporary building envelopes, such as engineered glazed façades, achieve high performance levels but often add a significant amount of embodied carbon. There is therefore an incentive to reduce the thickness of the glass panels, but the minimum thickness possible is often not governed by strength or manufacturing limits but rather by the deflection (serviceability) limits. Despite objective criteria guiding serviceability limits, user acceptance of deformation remains unexplored, leading to conservative designs. This paper introduces a novel method for measuring user satisfaction with glass deformations, aiming to establish acceptance thresholds comparable to objective criteria. The study involves a novel experimental campaign to assess volunteers' levels of perception and acceptance of various glass deformations. The glass was deformed using a bespoke electro-pneumatic system at levels corresponding to below, above, and at the current serviceability limit. The results demonstrate the feasibility of measuring human responses to deformations in the glazing and provide essential data for setting serviceability limits. The experiments and corresponding user satisfaction feedback indicate that the current serviceability limit of L/50, may be relaxed, thereby presenting opportunities for material efficiency, such as the adoption of thinner glass in facades. The methodology effectively captures human responses, revealing that changes in reflection were the primary reason for the perception of movement; leading to a higher perception of glazing movement and a lower acceptance at night. Overall, participants felt safe regardless of their prior knowledge on glass properties, and providing this information to participants did not improve acceptance, which was already sufficiently high. The findings from this research fill an important knowledge gap in understanding user acceptance of glass deformations, crucial for comprehensive user satisfaction assessments and evidence-based reductions in glazing thickness. ...
Conference paper (2024) - A.C. Chiucchiù, I. Misuraca, E. Brembilla, I. Pigliautile, M.J. Tenpierik, A.L. Pisello, P. de la Barra Luegmayer, Alessandra Luna-Navarro
Façade properties influence human responses in a multidomain manner and these interactions needs to be accounted for effective façades design, particularly to increase resilience to extreme heat. From existing research, it remains unclear whether the glazing colour properties can influence occupant thermal sensation, preferences, and acceptance, or whether higher temperatures affect glare sensation or view perception. This study investigates the combined influence of tinted glazing in façades through a preliminary experimental campaign with human participants exposed to varying glazing hues (neutral and blue) and indoor air temperatures. While previous research has examined the impact of coloured daylight on thermal and glare sensation under thermal conditions close to neutrality, this paper compares occupant responses at neutral and warm thermal conditions by performing repeated measurements.

An experiment was conducted to measure potential differences in human thermal sensation, acceptance, preference, and glare sensation under two thermal conditions (operative temperatures of 25°C and 30°C) and two daylight colours (neutral and blue). Thirty-nine participants were exposed to different combinations of temperature and glazing colour in a randomized order. Data were collected using questionnaires and thermal physiological sensors to capture human responses to these varying conditions. In terms of visual perception, the results demonstrate a distinction between the two visual scenarios, particularly regarding obstruction and glare at a neutral temperature. At the level of thermal sensation, the impact of blue-tinted glazing is not statistically significant with this number of participants. However, a slight difference is observed between the two scenarios at both temperature levels. ...
User experience and satisfaction with the facade play a significant role in user comfort and energy efficiency of buildings. This paper explores the concept of User-Facade archetypes to inform the user-centred design of shading devices based on the perceived level of importance of different environmental domains at the workplace. A questionnaire was developed to collect data on users’ perceived level of importance of different environmental domains, user characteristics and other preferences. Based on the associated level of importance of the domains affected by shading devices (thermal conditions, access to daylight, access to outdoor view, privacy and glare mitigation), users were then clustered into eight different archetypes, which associated different "weights" to each comfort domain. The study also found a significant correlation between the associated level of importance and the reported frequency of interaction with shadings because of thermal comfort, glare mitigation or privacy. Overall, users that associated high levels of importance to several environmental domains also reported high perceived levels of importance for personal control at the workplace. Only one archetype reported low importance for personal control at the workplace. Further work is required to validate these archetypes by capturing actual user behaviour and preferences in real workplaces. However, these findings provide preliminary and valuable insights into the possibility of clustering users on their preferences and using this for informing a more user-centred design or operation of shading devices. ...
Abstract (2023) - P. de la Barra Luegmayer, Alessandra Luna-Navarro, U. Knaack, A Prieto Hoces, Claudio Vásquez
Background. The automated operation of facades in buildings can positively impact indoor environmental quality (i.e. thermal regulation, acoustic control, air quality, and access to daylight and outside view) whilst reducing cooling, heating, and lighting energy demand. Conversely, several studies have also pointed out that the automated operation of dynamic façades can be disruptive to occupants and a source of discomfort when it does not meet occupant requirements. A number of factors affect occupant requirements regarding façade operation. However, the preference with which individual occupants perceive these requirements, in particular window visual effects, is yet to be understood, and it could inform better user-centred controls of automated facades. [...] ...