Light is not just about energy. It provides us the means to reveal spaces and volumes and interact with our environment. There is an increasing interest in natural day lighting, a valuable resource available for free every day. The energy used by artificial lighting in buildings is a major part of the energy use in buildings and if this can be reduced, consequently the emissions of carbon dioxide and greenhouse gases can be reduced. This can have an important effect in reducing global warming. This will also assist us significantly in the battle to solve our energy crisis. One square foot of a roof glass for sunlight is as good as 6 sq. ft of a window. And a window to the south and west of a building in the southern latitudes of India can mean more light, and more heat, too, for it is on the sun's 'friendly axis'.
Daylight can provide a welcome and dynamic contribution to the human experience in buildings and, can impact human performance. Most people appreciate daylight and also enjoy the outside view that windows provide. The therapeutic effect and the importance of access to sunlight is most noticeable when you are denied or deprived of its use.
The first and most obvious thing to understand is that daylight is variable: it varies with the season of the year, the time of day, and the weather. A careful study of the plans related to energy-efficient day lighting design will indicate where sufficient daylight is available, and where it will need to be supplemented.
A building's passive response to day lighting can enhance comfort and be cost-effective; the savings of course in energy and costs are obvious. The use of proper passive design systems ensures that you invite natural light pleasantly, while keeping heat of your home or workplace.
The easiest and cheapest way to get natural light into your home is with windows. Appropriate selection of locally available materials with thermally insulated properties can keep the home cool too, reducing the consumption of energy significantly.
There has to be enough light filtering in spaces that are common: corridors, pathways, walkways, basement stairways and such. Selection of colours that enliven walls and ceilings can make a subtle difference to the bounce you get of light in indoor spaces. Not just the design of individual buildings, the municipal rules of the land should set laws for setbacks between buildings. Where there are buildings jostling for space on a crowded street, rights of light have to be defined. It is important therefore to ensure that the profile of the building complies in all respects with the planning laws, and observes the right of the neighbour's light.
There are some areas in buildings where daylight can never reach and artificial light will always be required. With technological advancement, at places where there are limitations for use of natural light, solar lights or sky tubes are excellent alternatives for maximizing daylight and the technology of the reflector and reflectance of the tubes makes the amount of oncoming light very usable. In addition, they are much easier to install than a skylight.
Natural light is part of our biological needs. Intuitively, we prefer daylight to electric light. Spending at least four hours under the sun is vital for longevity and health, but that is a luxury lost for many urban millions.
With properly installed and maintained day lighting systems, natural light can add to quality of health, productivity, and safety of building occupants. Natural light helps maintain good health and is proven to be curative. In office spaces, the pleasant environment created by natural light decreases stress levels for office workers. Productivity increases with improved health of workers; with better productivity comes financial benefits for employers. Students also perform better with natural light. Safety is increased with better lighting conditions. The use of day lighting decreases utility costs and improves the well-being of building occupants. Maximizing its usage will not only help you keep lights off during the day it also saves you money by the minute.
The writer is Executive Chairman and Co-founder of BCIL ZED Homes.
