Skylights admit more light per unit area than windows and distribute it evenly over a space. Some details from Aswath M.U.

Eco-friendly architect Sathya Prakash Varanashi has explained the everlasting natural attractions and effects of skylights in the columns of ‘Green Sense' in earlier issues of PropertyPlus. There is no alternative to natural light and ventilation. We see large open spaces, courtyards and skylights in our traditional and historic buildings. Even in the modern residential as well as commercial buildings, open spaces and skylights are finding their place. The optimal area of skylights varies according to climate, latitude and the characteristics of the skylight, but is usually 4-8 per cent of floor area.

Sky lighting is a method for getting day light by placing openings and reflective surfaces to get effective internal lighting. By providing skylights we can maximise visual comfort and reduce energy use. Dimming/switching electric lights automatically in response to the presence of daylight is a process known as daylight harvesting. With proper skylight design, up to 80 per cent energy savings can be achieved in commercial and industrial applications.

Natural light and ventilation can be provided by means of air vents in the walls closer to roof, small openings in the roofs by perforated blocks or round pipe sections and large openings with proper design of grills and coverings. Skylights are normally placed on the roof of the building, with translucent acrylic diffusers and evenly distributed lighting. Skylights admit more light per unit area than windows and distribute it more evenly over a space.

Light and healing

Skylights are designed in a variety of shapes with different materials; hence a specific skylight can greatly influence the interior style of the building. The commercial skylight is generally used for energy-efficiency purposes; the residential skylight is more commonly used as simple lighting addition and to contribute to the overall look of the structure. Skylights have become popular due to the current research advocating that natural light not only helps concentration, but raises people's spirits, increases productivity, and aids the healing process.

The most common shapes include rectangular, triangular, oval, diamond, circular, multi-sided, and tubular. The materials include high quality corrugated iron, tile, metal, steel, plastic, glass and acrylic. Glazing is another important factor to consider while designing.

Skylights also help in ventilation and moisture control. This is achieved by providing an opening for hot air that naturally accumulates near the ceiling surface to escape. In this case, the skylight will act similar to a window, and can be opened either manually via chain or pole or automatically. Installing automatic skylight system will ensure maximum comfort and simplicity.

Styles, colours, shades

All these are gaining popularity as the latest form of light control and heat protection. Skylight shades can completely alter the dynamics of a room, by providing controlled light transmission and quality of light. Skylight shades provide privacy and protection against UV rays. Some of the common types are roller blinds, venetians, light-block shades and cellular shades. For example, the material in cellular shades filters direct sunlight in order to minimise glare, while venetians allow for light to be directed towards certain areas without blocking the outside view. Installing electric control system will eliminate the need for cords and poles. Motorised skylights are the most advanced designs for houses and office buildings for admitting natural light and controlling temperature levels just like regular skylights. Motorised skylights can be fully opened for ventilation purposes using remote control. Poorly constructed skylights may have leaking and safety problems. Using modern designs with proper installation/fixing procedures, we can eliminate issues of leaks and achieve greater energy efficiency and safety.

Acknowledgement: With inputs from G.C. Ranganath, Professor, BIT

[The author is Professor at Bangalore Institute of Technology and former Secretary General, ACCE (I)]