Daylight as a Driver for Healthier Energy Optimization
Renovations of existing buildings have primarily focused on the energy consumption and thermal comfort. This project involves health as a priority design parameter, and through an exemplary case study, the project examines how essential health aspects are better served.
Renovations of existing buildings have primarily focused on the energy consumption and thermal comfort. This project involves health as a priority design parameter, and through an exemplary case study, the project examines how essential health aspects are better served. The project focuses on facade design. The project involves daylight quality as a design parameter and focuses on the clearest glass quality on the market. Through a major housing, the study documents how aspects of health and energy are influenced by the quality of daylight/glass quality.
BACKGROUND
In recent years, research has provided new knowledge about the importance of daylight for human health1. People spend approx. 90% of their time in the indoor environment, exposed to low light intensity levels. This may impact overall health of the population by affecting circadian rhythms, sleep, and vitamin D levels.
OBJECTIVE
The project is the first of its kind to investigate the health effects and energy performance of two different glass types: 2-layered low-iron glass with high light transmittance, and 3-layered low energy glass with a lower light transmittance index. The project renovated 36 apartments using 2-layered low-iron glass and 36 apartments using 3-layered low energy glass.
METHOD
The project compares the effect of two different glass types on sleep quality, comfort and energy consumption for heating. By collecting data from the two identical buildings with a total of 72 inhabitants, before renovation 2016 (baseline) and after renovation 2017 (effect measurement) respectively.
RESULTS
The daylight intensity in the apartments with 2-layered iron-low glass was statistically significant higher (> 15%) compared to apartments with 3-layered low energy glass. The 3-layered glass completely blocked the UVB light whereas 2-layered low-iron windows transmitted 5 % of the UVB light (5%) and 20 % more light in the blue spectral range (460- 480 nm) .
A statistically significant deterioration in sleep quality of the residents in the housing with 3-layered low energy glass was found compared to the housing with 2-layered glass. Overall satisfaction with the daylight increased statistically significantly in the housing with 3-layered low energy windows. Lastly, 3-layered low energy windows did not provide any reduction in registered energy consumption for heating compared to 2-layered low-iron windows.
CONCLUSION
Low-iron 2-layered windows performed better than 3-layered low energy windows in an overall comparison including health- and energy performance together with life cycle assessment (LCA). This has implications for mental health both regarding hospital buildings and when renovating residential areas.
PERSPECTIVES
The results from this project may contribute to a discussion about the relation between glass quality and daylight quality and the results suggest further research performed in randomized largescale case studies.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Aalborg Universitet (Fredrik Bajers Vej) | ||
| Danmarks Tekniske Universitet (DTU) | ||
| Psykiatrisk Center | ||
| Rambøll | ||
| HAB |
