MAKING AN ECO-FRIENDLY HOME

Passive design is the key to sustainable building. It is a concept wherein the residence and the spaces within it benefit from natural sunlight, ventilation and even temperatures. It achieves this by using free, renewable sources of energy such as sun and wind to provide household heating, cooling, ventilation and lighting, thereby reducing or removing the need for mechanical heating or cooling.

It can also reduce energy use and environmental impacts such as greenhouse gas emissions. Interest in passive design has grown, particularly in the last decade or so, as part of a movement towards more comfortable and resource-efficient buildings.

The key elements of passive design include building location and orientation on the site, daylight, shading, thermal mass and ventilation. Each of these elements works with others to achieve comfortable temperatures and good indoor air quality.

      Key features of passive design:

1.    Location and orientation of the building: Orientation, layout and location on site will all influence the amount of sun a building receives and therefore its year-round temperatures and comfort.  It determines the solar energy in a home where we allow sun in during cooler months to provide warmth, while keeping summer sun out to prevent overheating.

2.      Day-light: Should be used as much as possible to light a home, both for energy efficiency and for the health and comfort of occupants.

3.  Shading: Providing shade over building openings and outdoor spaces can reduce temperatures and save energy.  It includes overhead chajjas , pergolas, verandas and even plants and trees surrounding the building periphery

4.    Thermal mass:  Is the capacity of a material to store heat energy. In building terms, it reduces temperature fluctuations by absorbing heat when the ambient temperature is hotter than the mass, and then releasing the heat when the ambient temperature falls below the temperature of the mass. When used effectively, this results in improving indoor comfort. By using walls of high density material like stone or concrete blocks the heat gain can be reduced making the temperatures optimum for the occupants.

5.    Ventilation: Ventilation is useful for passive cooling, where it should be considered along with other design features such like window size and placement. House having maximum windows in the south west direction allows good wind flow in Indian context.