The impact of natural light on our well-being

Natural light is of essential importance for our physical and mental health. A shortage of light creates numerous health issues and interferes with our performances. A lack of natural light also has major implications on the workplace. An optimal use of natural light improves the well-being and feeling of happiness of users and thereby is an essential element in the interior design.

Natural light and health

Sunlight plays an important role for our metabolism, internal clock and numerous other cellular processes. A lack of natural light for instance directly influences our quality of sleep, with all its consequences. Because of sleep deprivation your endocrine system can get disrupted, increasing the risk of obesity. Furthermore a shortage of natural light influences our mood negatively and can even cause depressions. Natural light is also important for the production of vitamin D. A shortage of vitamin D can cause fatigue, lethargy, muscle complaints at eventually weak bones.

Natural light on the workplace

For employees natural light and view to the outside come first as most important aspects of the workplace. Various studies show a shortage of natural light to interfere with their functioning and well-being. A study amongst over 1500 Northern-American employees for example shows over one third of the employees to consider their workplace to have insufficient natural lighting. 47% indicates they feel tired or very tired due to the absence of natural light or a window in the office. 43% indicates to feel glum due to the lack of light. A different study shows the positive effects of office environments with natural lighting. Employees reported a reduction of 51% of eyestrain, 63% of headaches and 56% of drowsiness.

light reflectance value

Besides the natural light itself, also surfaces like walls, floors and ceilings play a part regarding the quality of light in a space. To what degree is determined by the colors, structures and gloss of the materials used. These elements together decide to what degree light is being reflected or absorbed. Color is decisive but the structure and gloss can enhance or weaken the light reflection. For the structure in general counts the flatter and more even the structure, the better the material reflects light. With carpet a high light reflection can also be achieved. A flat surface structure will give better results than an irregular or deep texture. The use of glazed yarn can in this regard also contribute to a higher light reflection.

To what degree light is being reflected from a surface illuminated by a source of light, is measured by the light reflectance value (LRV). It concerns the total amount of visible and useful light (from all wavelengths and in all directions) which is being reflected by all surfaces on-site. LRV is being measured from value zero (a fully absorbed surface) to a hundred (a fully reflecting surface). Value zero is being considered to be completely black, value 100 perfect white. Colors with a high LRV reflect more light, reducing the need for artificial light to illuminate the room. Besides health benefits this provides a direct cost reduction and environmental benefits. Not insignificant in a time where the energy costs keep rising and it’s necessary to reduce our ecological footprint. Working smart with LRV-value in other words fits within energy efficient and sustainable building.

Natural light according to BREEAM, LEED aNd WELL

Natural light to be indispensable for our well-being is also underlined by certification systems like BREEAM, LEED and WELL. All three systems follow criteria in this domain for amongst others daylighting and view to the outside. Another criterion points are being credited on is the prevention of light disturbances caused by brilliance, reflection or glare by entering daylight. Within BREEAM the requirements concerning sufficient natural light (and comfortable artificial light) have been collected in the BREEAM-NL credit HEA01: visual comfort. Within LEED this is covered in the credit EQc7: Daylight. Within the WELL Building Standard this all is part of the concept Light.