Introduction: This study investigated the health effects of two different architectural glass types: A two-layered low-iron high transmittance glass and a three-layered low energy glass with lower transmittance. The study investigated how these glass types affected daylight conditions in 72 residential apartments, as well as health and satisfaction of the residents.Methods: The study installed high transmittance glass (light transmittance LT:0.82) in 36 apartments and low transmittance (LT:0.74) in 36 identical apartments. The study then analyzed the light transmittance of each glass type in the laboratory and analyzed the indoor environmental quality (IEQ) in eight representative apartments before and after renovation. Self-reported questionnaires were handed out and collected before and after renovation.Results: The results showed that the glass types differed significantly in measured daylight transmittance. The two-layered high transmittance glass transmitted 15% more visual light (380-750 nm) and 20% more light in the spectral range (460-480 nm), stimulating ipRGCs and circadian rhythm, when compared to three-layered low energy glass. In addition, significant differences were observed in the UV-B spectrum (280-315 nm). While two-layered high transmittance glass transmitted UV-B, three-layered low transmittance glass did not. During the 12-month study period, residents in apartments with three-layered low energy glass reported more difficulties sleeping (p = 0.05), higher satisfaction with daylight (p = 0.03) and higher satisfaction with ventilation (p = 0.04). Residents in apartments with three-layered low energy glass experienced fewer days with too cold indoor temperatures (p = 0.02), compared to residents with two-layered low-iron glass. The results of energy consumption for heating showed that two-layered low-iron glass reduced the energy consumption by 11.0%, while three-layered low energy glass reduced the energy consumption by 9.4%, compared to the year prior to renovation.Conclusion: The results contribute to a discussion about potential energy savings on one hand and potential non-energy benefits, such as daylight quality, overall health, and total economy/life cycle assessment of the built environment on the other hand. The results suggest further research performed in randomized large-scale studies.

Background: Retrospective studies conducted in psychiatric wards have indicated a shorter duration of stay for depressed inpatients in bright compared to dim daylight-exposed rooms, pointing to a possible antidepressant effect of daylight conditions. Dynamic LED lighting, aiming to mimic daylight conditions, are currently been installed in several hospitals, but their feasibility is poorly investigated. Methods: To investigate the feasibility of these systems, we developed and installed a LED-lighting system in four rooms in a psychiatric inpatient ward. The system could function statically or dynamically regarding light intensity and colour temperature. The system consisted of (A) a large LED luminaire built into the window jamb mimicking sunlight reflections, (B) two LED light luminaires in the ceiling and (C) a LED reading luminaire. In the static mode, the systems provided constant light from A and B. In the dynamic mode, the system changed light intensity and colour temperature using A, B and C. Patients with unipolar or bipolar depression were randomised to dynamic or static LED lighting for 4 weeks, in addition to standard treatment. Primary outcome was the rate of patients discontinuing the trial due to discomfort from the lighting condition. Secondary outcomes were recruitment and dropout rates, visual comfort, depressive symptoms and suicidal ideation. Results: No participants discontinued due to discomfort from the LED lighting. Recruitment rate was 39.8%, dropout from treatment rates were 56.3% in the dynamic group and 33.3% in the static group. 78.1% in the dynamic group were satisfied with the lighting compared with 71.8% in the static group. Discomfort from the light (glare) was reported by 11.5% in the dynamic group compared to 5.1% in the static group. Endpoint suicidal scores were 16.8 (10.4) in the dynamic and 16.3 (14.9) in the static group. The lighting system was 100% functional. The light sensor system proved unstable. Conclusion: Dropout from treatment was high primarily due to early discharge and with a lack of endpoint assessments. The feasibility study has influenced an upcoming large-scale dynamic lighting efficacy trial where we will use a shorter study period of 3 weeks and with more emphasis on endpoint assessments. The lighting was well tolerated in both groups, but some found intensity too low in the evening. Thus, we will use higher intensity blue-enriched light in the morning and higher intensity amber (blue-depleted) light in the evening in the upcoming study. The light sensor system needs to be improved Trial registration: ClinicalTrials.gov: NCT03363529

This paper summarises findings from two workshops evaluating a series of views in various settings by an interdisciplinary group of experts. In the first one (Trondheim, June 2022), ten experts visited and assessed views from nine rooms. In the second one (Lausanne, June 2023), eleven experts assessed window views from four spaces. The workshops’ main objective was to develop and test multi-method assessments of window views. During both workshops, participants completed a survey that included close and open-ended questions about the perceived quality of the room and the view. Participants also measured lux level, took photographs, made hand drawings of the view, and answered a questionnaire about their mood and the environmental conditions in the room. After the workshop, point-in-time daylight simulations were performed for the visited rooms. The paper describes, compares, and recommends the use of the aforementioned methods depending on the type and complexity of the view, and the space, the evaluators’ professional background, and the type of collected data. It also discusses the overlap of the methods and estimates the preparation time, time spent on site, and the amount of work after the visit. Finally, it recommends the use of the tested methods depending on the application.

Introduction Research has provided novel insights into how light stimulates circadian rhythms through specialised retinal ganglion cells to the suprachiasmatic nucleus. In addition, there has been a revolution in light-emitting diode (LED) technology, leading to tunable LED light sources and lighting systems, enabling 24-hour dynamic light scenarios with bright blue-enriched short wavelength light during the day and dim evening light, stimulating the circadian system. These dynamic LED lighting systems are now being implemented at hospitals without adequate understanding of how it may affect the health and well-being of patients and staff. Methods and analysis An optimised dynamic LED lighting scenario is investigated at a newly built psychiatric hospital in Copenhagen. In the 12 months baseline period, a standard lighting scenario with dynamic colour temperature and fixed light intensity is investigated. In the following 12-month intervention period, a new DEL scenario is investigated, having dynamic colour temperature as well as dynamic light intensity with a higher daytime and lower evening-time melanopic daylight equivalent illuminance. This setting is furthermore adjusted for geographical orientation to compensate for differences in sunlight access in wintertime. The study uses a quasiexperimental design comparing patients admitted in the two study periods. Prior to each of the study periods, daylight and the contribution from the LED-lighting scenarios was measured. Patient sociodemographic and mental health data will be retrieved retrospectively from electronic medical records and by questionnaires administered in the two periods, evaluating lighting, noise, sleep quality and quality of life. Primary outcome is the proportion of patients receiving pro re nata medications. Secondary outcomes are the length of stay, sleep onset latency, sleep quality and quality of life. Ethics and dissemination No ethical issues are expected. The results will be disseminated through peer-reviewed international journal, lectures, posters and interviews. Trial registration number NCT05868291.

Major Depressive Disorder (in the following termed depression) and bipolar disorder are frequent affective disorders with a lifetime prevalence of 15–20% [1, 2] and 4–5% [3], respectively. Seasonal...

Background In many Danish schools, the indoor environmental quality (IEQ) is challenged and studies document a poor IEQ in a majority of existing schools. Municipalities cannot afford comprehensive renovations and expensive mechanical ventilation solutions, hence public schools often suffer from poor indoor environment conditions. This study tests a new façade based, demand-controlled ventilation solution called NOTECH in the renovation of school. The study tests NOTECH vs. existing mechanical ventilation solution, comparing performance of both solutions at Skovbrynet Skole in Denmark. Methods The project investigates the effect of the NOTECH solution in a primary school classroom, comparing it to a similar classroom with conventional, mechanical ventilation. Methodically, indoor environmental quality and energy performance is monitored in the two identical classrooms during one school year 2018 - 2019. Results The results show that both systems keep the conditions within acceptable limits and CO2 levels below 1000 ppm, which is the requirement according to the Danish Building Regulations. In terms of costs, the NOTECH system has a lower overall cost than the mechanical ventilation system, with total estimated costs for installation, heating, electricity and maintenance amounting to approximately 35% of the mechanical system’s costs. Finally, the results show that the NOTECH solution has a smaller embedded CO2 footprint for building materials, reducing the estimated carbon load by 95% compared to the mechanical ventilation solution. Conclusions While the performance of the both systems complies to the Danish Building Regulations, the indoor environmental quality between systems differs significantly. Results showing a higher air-temperature and lower relative air-humidity in the classroom with mechanical ventilation during winter and lower CO2 levels in the mechanically ventilated classroom during winter and summer. Costs for implementation, energy consumption for heating and CO2 footprint for building materials are significantly lower for the NOTECH solution, compared to the mechanical solution.