Many researches have shown how well-lit environments can boost productivity and improve people comfort, providing mental and visual stimulations that can regulate the human circadian rhythms. Additionally, a wise optimization of daylight can heavily lead to energy savings, thanks to reduced artificial lights.
How exactly does daylight affect our health and wellbeing?
The architectural definition of daylight is’the interplay of natural light and building form to provide a visually stimulating, healthful, and productive interior environment’. Also for a space to be daylit, it must use daylight as the main source of illumination, optimizing its use.
Under daylight conditions human vision is better than under artificial light, this is mainly due to the range of wavelengths which allow a better colour rendering. Also, short wavelengths, which characterize natural light, have been found to increase alertness as compared to longer wavelenghts. However, when we are exposed to bright spaces we can experience glare or direct sunlight which can also be a cause of eye damage.
In addition, it is important not to have too much contrast in a space, which is a result of nonuniform daylight distribution. In fact, when we move from a very bright surface to a dark one our eyes need to adjust to compensate for the gap in brightness.
Human health is affected by exposure or not exposure to daylight in multiple ways. Recent researches have shown how the circadian cycle of human beings, that regulates our body’s sleep at night and alertness during the day, is manipulated by the relationship with daylight.
A Northwestern University study (2013) on sunlight and daylight and people comfort, analyzed how employees react to different exposures to natural light. It has been discovered that employees that work in offices with windows sleep better and on average 46 minutes more that those colleagues in offices without any windows. The reason being that sunlight tells our bodies when to be awake and when to sleep and if this cycle is compromised people can experience difficulties in sleeping at night.
Also daylight is responsible for the production of vitamin D, which has a relevant role in maintaining a strong immune system and can protect us from getting sick too often.
Although studying the link between our mood and daylight is very difficult, because of the multiple contributing factors coming into place, an increasing larger amount of research is indicating that exposure to daylight can boost productivity in the workplace between 10% and 20%.
Having a view on the outside put people in contact with the outside world, the weather, the time of the day and provides a stimulating sight and variety. This is strictly linked with reduced stress and workplace satisfaction.
Obviously not all the views are equally interesting and satisfactory, and also direct sunlight can distract and generate overheating at certain time and days of the years, therefore it’s equally important to allow for shading controls.
Generally, a glazed area of a room should be 24-30% of the wall surface, according to engineering limitations, which is a good proportion for a window/wall ratio.
It is very important for designers to integrate considerations in regards to daylighting strategies early in the design stage and make sure to allow occupants a certain degree of control over the work space daylighting conditions.
Shading systems are effective tools to regulate the amount of daylight a space will be subject to, and there are a variety of systems that can be applied according to the specific site requirements (see schematics below).
Finding the balance between natural daylight and artificial light is a challenge for architects and sustainable designers, and excessive direct sunlight often is the result of a bad facade design. However, optimal building orientation, building shape optimisation and thermal mass along with a wide variety of shading systems can be integrated in building design to achieve more comfortable and happy spaces, in which ultimately we spend most of our lifetime.
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