Everyday light exposure plays a vital role in circadian entrainment, especially during twilight. Electric lighting can supplement daylight anytime, enabling unlimited human activity; hence, many struggle to combine a healthy sleep regime with social constraints. Dusk/dawn simulators have been developed to compensate for the lack of twilight exposure and are typically applied in residential environments, where people usually sleep. Innovations in tuneable lighting control enable home-integrated dusk/dawn simulation, but it is essential to understand their performance and acceptance in real-life situations. A pilot field study was executed in 14 Swedish apartments and tested 3 lighting control scenarios for effects on behaviour, well-being and sleep patterns during the winter. Data were collected using wearable actigraphy, weekly surveys and interviews. The light intervention influenced wake- and bedtimes and contributed to slightly more consistent sleep schedules. Subjective responses emphasised that the dawn simulation assisted in a calm and peaceful wake-up, providing extra time for morning activities. The dusk simulation was a reminder to go to bed, but not all participants appreciated the light quality. Satisfaction and acceptance of the pre-programmed dusk/dawn control system were very high, provided there would be increased control for the residents.

Good lighting is one of the most important comfort factors in residential buildings. In creating a comfortable and restorative living space, the effects of light, both visual and effects beyond vision, play a crucial role. Daylight is considered an essential factor for indoor environments, which can benefit occupants’ health as well as lower energy use. This study investigated the potential daylight exposure for 10 apartments in Sweden, using metrics to quantify both visual effects and effects beyond vision and to understand the relationship between the light situation in the apartments and well-being metrics collected from occupants during a field study. Computational modelling of daylight conditions for visual effects and effects beyond vision was performed. Statistical analysis was utilised to investigate the possible relationship between the apartments’ daylight potential and the self-reported well-being of the occupants. The results show variations of light exposure for apartments in different seasons. Furthermore, possible relationships between well-being metrics and daylight exposure changes were observed despite being possibly influenced by seasonal light level contrasts.

Lighting in the built environment affects different aspects, ranging from building performance in terms of costs and energy consumption to human well-being in terms of thermal comfort, visual effects, and beyond-vision effects. Buildings optimised for specific performance metrics rarely consider different aspects simultaneously, leading to sub-optimised, unbalanced, or non-trade-off solutions. Therefore, multi-objective optimisation has commonly been used to overcome conflicting performance objectives. Recently, light effects beyond vision gained more interest in building design but it is unclear if and how they are integrated with other existing building performance metrics and simulation workflows. A scoping review investigated the state-of-art in multi-objective lighting design optimisation regarding building performance and human well-being focusing on performance metrics, simulation workflows, and the overall information flow. Results show that metrics for beyond-vision effects are not integrated with other human well-being and building performance metrics. The simulation workflows included multiple steps and computational tools in multi-objective optimisation. This process has limitations such as a long simulation time, no ubiquitous integrated tool, and a reduced information flow.

A hybrid workstyle is becoming more common post-COVID-19, and longer occupancy hours at home are increasing household electricity consumption. Small homes are regarded as a potential for improving energy efficiency in the residential sector, and a home consists of mixed-function spaces with dynamic occupancy behaviors. These underpin the opportunity to optimize presence sensing lighting in small homes for energy efficiency and user-behavioral needs. A comprehensive overview of presence sensing approaches, comparing four types of non-wearable sensors connected to home lighting is made. A bibliometric mapping of the reviewed literature visually reinforces a significant research gap that presence sensing studies were not connected to home lighting but inclined toward the commercial and institutional context. Next, a non-exhaustive example of commercially available presence sensing products applicable to residential lighting for small homes is analyzed, and their general characteristics and technologies are synthesized. The literature and product overview identified five significant product knowledge gaps. Incorporating the gathered information leads to the proposal of a conceptual flexible radar-based sensor (prototype design), addressing a wish list with three important criteria to optimize future presence sensing lighting in a mixed-function small home. Future radar sensing studies are expected to develop an anticipatory lighting system that processes real-time multi-user vital signals for smarter localized and personalized lighting options for (small) living environments.

The relationship between everyday light exposure and sleep was studied for office workers. The study was conducted during the upswing of the COVID-19 pandemic, enabling a comparison between Office and Home Workdays. Fifteen full-time office employees were monitored for a period of 4–6 weeks. They wore a light-tracking device on their clothes and had a sleep tracker at home. Compared to an Office Workday, light exposure was lower in the afternoon and total sleep time was almost 5 minutes longer on a Home Workday. Sleep efficiency was the same on both workday types. A higher median illuminance level in the afternoon was significantly related to later sleep onset on an Office Workday. Higher median illuminance levels in the morning were related to earlier awakening. Counter to expectations, higher light levels in the evening were also related to earlier awakening. Everyday light exposure matters for sleep quality but may affect circadian functioning differently than the often more extreme light interventions employed in laboratory experiments. Moreover, differences in outcomes between Office and Home Workdays signal the need for further investigation to provide supportive light levels during workhours.

Social constraints posed by work schedules influence sleep duration and timing. Everyday light exposure can help (or hinder) sleep outcomes. This study investigated the differences in the relationship between light exposure and sleep outcomes on days with and without social constraints using ambulatory assessment for 4?6?weeks for 15 office employees. The effects of light on sleep were investigated for both clock time and wake time (related to individual sleep times). Participants were exposed to more light during the morning and afternoon on workdays, and sleep times were later on days without social constraints. The relationship between light exposure and sleep was more pronounced, or sometimes even only present, for days without social constraints. In addition, no differences were found between clock time and wake time, which underlines the complexity of the relationship between everyday light exposure and sleep. Despite increased light exposure during workdays, the effects of light on sleep were more pronounced on days without social constraints. It may signal that office workers need a more substantial circadian stimulus (i.e. higher light exposure) for light to influence sleep outcomes on days with social constraints.

Residential lighting control can assist in creating a comfortable atmosphere, providing information, and supporting well-being. Field studies are used to investigate lighting control, but study protocol customisation or personalisation may be required due to actual life events and situations. An 8-week field study tested three protocols for effects on behaviour, well-being, and sleep patterns and was executed in 14 apartments during the winter. Light amount and timing were controlled: residents woke up with a dawn simulation, experienced lights turn-off as an indication to leave for work, and were prepared for bed during a dusk simulation scenario. Sleep trackers results showed later and more wide-ranged wake-up and bedtimes than assumed. As expected, the apartments’ different floorplans challenged comparable light exposure. Unexpectedly, several participants requested a reduced wake-up frequency and reported sleeping elsewhere on Fridays and Saturdays. Everybody experienced a full dawn simulation, but some people left home soon after wake-up, calling for lighting control customisation. Real-time field applications may demand a certain level of customisation or personalisation, affecting intentions and results. Discussing and documenting (un)intentional adjustments during final interviews and in scientific publications can benefit in explaining findings and further research.

Current presence-sensing technologies for energy-efficient lighting control and building optimisation are (i) catered to commercial and institutional environments, and (ii) focused on lamp technology and occupancy detection. They often ignore user behaviour characteristics, which significantly influence energy consumption. Therefore, this study aims to identify alternative sensing techniques as part of a lighting control system that can energy-efficiently support user's behavioural needs in mixed-function residential spaces. An exploratory study investigated the optimal placement of a non-wearable radar sensor to detect an imitated user's breathing frequency at varying pre-set horizontal distance positions, and the sensor's performance was validated with a spirometer. The procedure measured a balloon's radar-detected distance, radar-detected breathing frequency, and spirometer-registered breathing frequency at each pre-set position. The radar sensor detected all simulated breathing frequencies with almost 100% data accuracy but was not comparable in detecting all distances. The radar offers a less intrusive short-range presence-sensing for homes, accurately detecting breathing frequencies in a contactless way between 0.2m to 0.8m. Further investigations are recommended to develop radar sensing that could predict lighting options based on user's objective feedback.