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Correlational analysis, such as linear regression, does not imply causation. This paper introduces and applies a causal inference framework and a specific method, regression discontinuity, to thermal comfort field studies. The method utilizes policy thresholds in China, where the winter district heating policy is based on cities' geographical locations relative to the Huai River. The approximate latitude of the Huai River can be considered as a natural, geographical threshold, where cities near the threshold are quite similar, except for the availability of district heating in cities north of the threshold, creating a situation similar to a randomized experiment. Using the regression discontinuity method, we quantify the causal effects of the experiment treatment (district heating) on the physical indoor environments and subjective responses of building occupants. We found that mean indoor operative temperatures were 4.3 °C higher, and mean thermal sensation votes were 0.6 warmer due to the district heating. In contrast, using conventional correlational analysis, we demonstrate that the correlation between indoor operative temperature and thermal sensation votes does not accurately reflect the causal relationship between the two. We also show that the indoor operative temperature could be either positively or negatively correlated with occupants’ thermal satisfaction. However, we cannot conclude that increasing the indoor operative temperature in these circumstances will necessarily lead to higher or lower thermal satisfaction. This highlights the importance of causal inference methods in thermal comfort field studies and other observational studies in building science, where the regression discontinuity method might apply.

Abstract International building certification systems, such as the WELL and Leadership in Energy and Environmental Design (LEED) standards, play a pivotal role in the design of healthy and sustainable buildings. While LEED adopts a holistic approach to designing healthy and sustainable buildings, the WELL standard has a strong emphasis on human health, comfort, and well-being. Although prior research has revealed inconsistent results for occupant satisfaction in office buildings with WELL certification compared to buildings without WELL certification, or are certified using another certification system (e.g., LEED), most of these comparisons tend to lack methodological rigor. This study used a statistical procedure to match and compare 1634 occupant surveys from LEED-certified buildings to 1634 surveys from WELL-certified buildings. Six important architectural and experiential parameters were matched, masking their influence on the outcome. Overall building and workspace satisfaction was high in both WELL-certified buildings (94% and 87%) and LEED-certified (73% and 71%). We found that there is a 39% higher probability of finding occupants who are more satisfied in WELL-certified buildings compared to LEED-certified buildings, indicating occupant satisfaction is higher in buildings with WELL certification. Although we were unable to pinpoint the reason for higher occupant satisfaction in WELL-certified buildings, the results consistently showed that perceived indoor environmental quality was enhanced across all parameters except for the amount of space.

Long-term monitoring of the thermal environment in office buildings has become increasingly relevant with the rise of wireless sensor networks. However, there is a notable absence of explicit guidelines for implementing monitoring strategies in such contexts. This lack of direction can lead to inconsistent deployment of sensor networks, resulting in higher maintenance costs and inaccurate long-term assessments of thermal conditions. Based on data analyses of high-accuracy, high-frequency field measurements conducted over a year or longer across multiple offices in Sydney and Shanghai, this study proposes a strategy for long-term temperature monitoring. The strategy advises practitioners to prioritize considerations such as air-conditioning type, room size, and space function when selecting ''representative'' sensor locations. Typically, sampling every 30 min is deemed adequate for shared offices where an error margin of ±0.5°C is acceptable. For environments with stable indoor temperatures, less frequent sampling intervals suffice. A power regression model tailored for offices equipped with central AC and no operable windows was developed to predict the maximum allowable sampling interval based on several days of indoor temperature monitoring in winter. Regarding monitoring duration, the study advocates a preferred sampling period of one year to comprehensively capture seasonal variations. Alternatively, a minimum monitoring period of four to six months commencing in late spring or early summer is identified as potentially sufficient. These findings offer valuable insights for optimizing long-term thermal monitoring practices in offices and may contribute to expanding the scope of thermal comfort standards.

Abstract Sleep is a pillar of human health and wellbeing. In high- and middle-income countries, there is a great reliance on heating, ventilation, and air conditioning systems (HVAC) to control the interior thermal environment in the bedroom. However, these systems are expensive to buy, maintain, and operate while being energy and environmentally intensive—problems that may increase due to climate change. Easily-accessible passive and low-energy strategies, such as fans and electrical heated blankets, address these challenges but their comparative effectiveness for providing comfort in sleep environments has not been studied. We used a thermal manikin to experimentally show that many passive and low-energy strategies are highly effective in supplementing or replacing HVAC systems during sleep. Using passive strategies in combination with low-energy strategies that elevate air movement like ceiling or pedestal fans enhances the cooling effect by three times compared to using fans alone. We extrapolated our experimental findings to estimate heating and cooling effects in two historical case studies: the 2015 Pakistan heat wave and the 2021 Texas power crisis. Passive and low-energy strategies reduced sleep-time heat or cold exposure by 69–91%. The low-energy strategies we tested require one to two orders of magnitude less energy than HVAC systems, and the passive strategies require no energy input. These strategies can also help reduce peak load surges and total energy demand in extreme temperature events. This reduces the need for utility load shedding, which can put individuals at risk of hazardous heat or cold exposure. Our results may serve as a starting point for evidence-based public health guidelines on how individuals can sleep better during heat waves and cold snaps without relying on HVAC.

Identifying disease-specific imaging features of idiopathic Normal Pressure Hydrocephalus (iNPH) is crucial to develop accurate diagnoses, although the abnormal brain anatomy of patients with iNPH creates challenges in neuroimaging analysis. We quantified cortical thickness and volume using FreeSurfer 7.3.2 in 19 patients with iNPH, 28 patients with Alzheimer's disease (AD), and 30 healthy controls (HC). We noted the frequent need for manual correction of the automated segmentation in iNPH and examined the effect of correction on the results. We identified statistically significant higher proportion of volume changes associated with manual edits in individuals with iNPH compared to both HC and patients with AD. Changes in cortical thickness and volume related to manual correction were also partly correlated with the severity of radiological features of iNPH. We highlight the challenges posed by the abnormal anatomy in iNPH when conducting neuroimaging analysis and emphasise the importance of quality checking and correction in this clinical population.

Abstract Wearable inertial measurement units (IMUs) are being used to quantify gait characteristics that are associated with increased fall risk, but the current limitation is the lack of contextual information that would clarify IMU data. Use of wearable video-based cameras would provide a comprehensive understanding of an individual’s habitual fall risk, adding context to clarify abnormal IMU data. Generally, there is taboo when suggesting the use of wearable cameras to capture real-world video, clinical and patient apprehension due to ethical and privacy concerns. This perspective proposes that routine use of wearable cameras could be realized within digital medicine through AI-based computer vision models to obfuscate/blur/shade sensitive information while preserving helpful contextual information for a comprehensive patient assessment. Specifically, no person sees the raw video data to understand context, rather AI interprets the raw video data first to blur sensitive objects and uphold privacy. That may be more routinely achieved than one imagines as contemporary resources exist. Here, to showcase/display the potential an exemplar model is suggested via off-the-shelf methods to detect and blur sensitive objects (e.g., people) with an accuracy of 88%. Here, the benefit of the proposed approach includes a more comprehensive understanding of an individual’s free-living fall risk (from free-living IMU-based gait) without compromising privacy. More generally, the video and AI approach could be used beyond fall risk to better inform habitual experiences and challenges across a range of clinical cohorts. Medicine is becoming more receptive to wearables as a helpful toolbox, camera-based devices should be plausible instruments.

This paper investigates the pattern of change in occupants’ satisfaction with the Indoor Environmental Quality (IEQ) of their workspace over time. Analyses were performed on a cumulative (2012–2023) database of responses to a Post-Occupancy Evaluation survey in Australia. 20,400 questionnaire responses from 226 office buildings were classified into five groups based on the length of time respondents had occupied their workspace. Associations between workspace satisfaction and the length of time respondents had occupied their workspace were also analysed for different gender and age cohorts. Our results show that occupant satisfaction generally decreased with the length of time they had been allocated to their present workspaces (the ‘honeymoon-hangover’ effect). People who have occupied their workspace for more than 5 years expressed lower overall satisfaction with their workspace than those who have been there for less than 6 months. The same pattern was observed for occupants’ satisfaction with other IEQ dimensions including building image and maintenance, indoor air quality, spatial comfort, and thermal comfort. This ‘honeymoon-hangover’ effect was evident across genders and age groups. Furthermore, there was negligible difference between the two genders on the ‘honeymoon-hangover’ effect, although thermal comfort and indoor air quality were generally less satisfactory for women than men. Respondents aged 30 yrs or less showed a larger decline in satisfaction over time compared to those over 50-yrs old. Within the 30-year-or-under age group, occupants who had spent more than 5 years at their workspaces consistently registered the lowest satisfaction score across all IEQ dimensions. Implications and impacts: The findings in this study have significant implications for the design of Post-Occupancy Evaluation (POE) surveys and for facility managers aiming to enhance occupants' satisfaction with their workspace and workplace.

Previously unpublished data from over 600 office buildings in the Center for the Built Environment (CBE) Occupant Survey database are used to perform a systematic analysis of dissatisfaction in contemporary workspaces. A total of 81% of respondents expressed dissatisfaction with at least one aspect of their workspace, and 67% with more than one. Acoustics were the most common source of dissatisfaction, particularly related to people talking, speech privacy, and phones. Other challenges included a perceived lack of control over the temperature and insufficient space, along with other associated problems of densely populated offices. The analysis shows that context matters when understanding occupant dissatisfaction. Occupants of open-plan offices with low or no partitions were almost twice as likely to complain about their workspace than someone in a private, enclosed office. Being near a window decreased the likelihood of dissatisfaction compared with those who were not near a window. There was a clear relationship between self-perceived performance and satisfaction with the indoor environment. Dissatisfaction profiles found that acoustics, space, and privacy-related items co-occur for many occupants dissatisfied with more than one workspace aspect. 'Practical relevance' Post-occupancy surveys are a useful tool for evaluating whether an office environment supports occupants while conducting their work. While highlighting the successes is important, complaints from dissatisfied occupants can identify issues and pinpoint reasons why spaces do not meet expectations. The reported challenges generally relate to the simultaneous reduction in control and personalization with increasingly open and densely populated layouts. Occupant dissatisfaction may impact performance given the reported relationship between satisfaction with the environment and feeling supported by the workspace to complete work tasks. The themes emerging from this analysis identify common dissatisfaction sources that can serve as an empirical basis to identify common problems in contemporary workspace designs.

Heating and cooling indoor environments is responsible for the largest share of energy consumption in buildings [...]