What is VISUAL COMFORT?
The physical aspect of VISUAL COMFORT
VISUAL COMFORT is a subjective reaction to the quantity and quality of light within any given space at a given time. The concept of visual comfort depends on our ability to control the light levels around us. Both too little and too much light can cause visual discomfort. Just as importantly, changes in light levels or sharp contrast can cause stress and fatigue, as the human eye is permanently adapting to light levels. It can vary depending on the following factors: time of exposition, type of light, the color of the eye (light-colored eyes tend to bemore sensitive) as well as the age of the person.
VISUAL COMFORT encompasses a variety of aspects, such as aesthetic quality, lighting ambiance and view:
- Views of outside space and connected to nature
- Light quality
- Absence of glare
Working in a window-less office, even under adequate light conditions, and working in an office with a view, are totally different experiences. Abundant scientific studies show positive impacts of the latter on mood and job satisfaction.
The physiological aspect of VISUAL COMFORT
Assessing a visual environment requires the analysis of three main factors – the sources of light (artificial/natural), the distribution of light within the space (color, intensity) and its perception.
It is only recently that scientists have begun to understand how light influences our body and mind. Light has a direct effect on the regulation of various biological functions, such as sleep, mood, and alertness. The sun (or an electric light bulb, if the light source is artificial) emits propagating energy, of which a limited range of wavelengths, included between infrared to ultraviolet, is perceptible to the human eye as light. Our perception of light is determined by the amount of radiation energy that enters the eye and the spectrum of this light. Knowing more about light and how to control it is crucial, as light directly influences our health and well-being, as well as our perception and experience of the surrounding environment.
The socio-psychological aspect of VISUAL COMFORT
Our personal history and culture also shapes the way we appreciate light and visual environments. Extreme variations in preferred range of illuminance exist depending on age and culture. For instance, preferred light colors in Asia are quite different from those in Europe.
DID YOU KNOW?
Having a better view out of an office window is associated with better overall performance, with productivity increased by 7%–12%
DID YOU KNOW?
In hospitals, it has been observed that patients in rooms that are well daylit need up to 30% less pain-relief than others that they recover faster and return home in much better spirits.
postoperative analgesic medication usage: A prospective study of spinal surgery patients.
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daylight environments on patient average length of stay (ALOS) in a healthcare facility. Building and
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surgery. Science, 1984, 224: 420-421.
Natural daylight helps contributing to VISUAL COMFORT
Until 20 years ago, most of the research on lighting was focused on how to provide enough artificial light to perform certain tasks. Since then, however, new demands for energy efficiency in buildings, as well as questions about the impact of artificial light on people’s health, have led us to re-evaluate the benefits of natural daylight – and re-consider the way we build for visual comfort.
Natural daylight is the illumination source to which our eyes are naturally adapted, so that we nearly always find it more comfortable than artificial lighting. When choosing a home, good natural light is often cited as the second most important criteria. In office environments, occupants have a preference for daylight and views, related to job-
satisfaction and well-being. Daylight provides information about the hour of the day, the seasons, and the weather which helps to maintain our sense of psychological and social balance.
Designing for VISUAL COMFORT in buildings
Office occupants with more light exposure during work hours sleep longer, and enjoy better sleep quality, more physical activity and a better quality of life compared with office workers with less light exposure in the workplace.
It is now commonly accepted that the key to visual comfort in buildings is based on:
- Access to views/the outdoors,
- Daylight provision
o In sufficient quantity
o Distributed homogeneously throughout the space (no dark areas or flickering),
o In good combination with artificial light, adapted to the visual task and allowing a good color rendering
o Controlled to ensure the absence of glare and high contrasts,
- In an aesthetically pleasing space
The availability of natural light varies constantly – depending on the geographical location, the season and time of day – so ensuring a continuous quality of light to provide optimal visual comfort is a sophisticated design challenge.
Building design and choice of materials and equipment obviously play a decisive role. Because natural light varies all the time, ensuring a constant quality of light involves controlling its intensity. This can mean either reducing too much incoming light by shading, or compensating for low light levels with artificial light. Increasingly sophisticated control systems are able to manage all these variables, and help achieve a successful balance in the combined use of artificial light and daylight.
VISUAL COMFORT in buildings is important for the well-being and productivity of occupants. The challenge is to think of an environmental performance building by taking into consideration the natural daylight parameters. The solutions can be the construction of sun-oriented buildings or the use technology like electrochromic glazing, letting the natural light entering the space.
MULTI COMFORT buildings are full of natural light without glare, have rich colors, making close-up work easy from even light distribution and bring the outdoors inside, connecting you with nature and improving your mood.
Products and solutions for visual design
Saint-Gobain offers several product categories that have a direct impact on VISUAL COMFORT:
- Transparent products, such as glass, films or architectural membranes, which allow access to daylight and views through windows, doors and partitions
- Translucent products that allow daylight whilst preserving privacy
- Opaque interior products, such as wall coverings, ceiling or flooring products, which can contribute to the distribution of daylight and to the aesthetics of the space
Examine the evidence of VISUAL COMFORT
“A comprehensive US study in the late 1990s suggested a link between the physical office environment and retention and recruitment of staff. One of the most significant results was the importance workers placed on the ‘visual appeal’ of the workplace compared to many other factors.”Source: American Society of Interior Designers (1999) Recruiting and Retaining: Qualified Employees – by design.
“A study in 2011 investigated the relationship between view quality, daylighting and sick leave of employees in administration offices of Northwest University Campus. Taken together, the two variables explained 6.5% of the variation in sick leave, which was statistically significant.”Source: Elzeyadi I (2011) Daylighting-Bias and Biophilia: Quantifying the Impact of Daylighting on Occupant Health, August 2014.
Marks and Spencer’s Cheshire Oaks location saw high customer satisfaction and a 22% increase in employee satisfaction by enhancing the customer experience through better daylighting, better flow-through of air, and better materials.Source: http://betterplacesforpeople.org/index.php/blog/healthy-retail-places-are-a-quick-win-for-retailers/
“A study of workers in a Californian call centre found that having a better view out of a window was consistently associated with better overall performance: workers were found to process calls 7% to 12% faster. Computer programmers with views spent 15% more time on their primary task, while equivalent workers without views spent 15% more time talking on the phone or to one another.Source: Heschong Mahone Group (2003) Windows and Offices: a Study of Worker Performance and the Indoor Environment (Technical Report) for California Energy Commission, 2003, pp 2-4.
“Office workers with more light exposure at the office have longer sleep duration, better sleep quality, more physical activity and better quality of life compared to office workers with less light exposure in the workplace, according to a study from Northwestern Medicine and the University of Illinois at Urbana- Champaign published in the Journal of Clinical Sleep Medicine. Employees with windows in the workplace received 173% more white light exposure during work hours and slept an average of 46 minutes more per night than employees who did not have natural light exposure in the workplace. Workers without windows reported poorer scores than their counterparts on quality of life measures related to physical problems and vitality, as well as poorer outcomes on measures of overall sleep quality and sleep disturbances. There was also a trend for workers in offices with windows to carry out more physical activity than those without windows. This highlights the importance of exposure to natural light to employee health and the priority designers of office environments should place on natural daylight exposure for workers.”Source: www.technology4change.com, 12th August 2014 (Technology4change is published by the BRE Trust, an independent charity dedicated specifi cally to research and education in the built environment.)
“A seminal study over 20 years ago showed that workers who had window views of nature felt less frustrated and more patient, and reported better health than those who did not have visual access to the outdoors or whose view consisted of built elements only.”Source: Environmental Audit Committee report (www.gov.co.uk)