Rising energy & material costs and sensitivity towards the environment have increased the importance of fenestration more than ever before, says Aparna Reddy, Director, Aparna Enterprises Pvt. Ltd.

Are the fenestration techniques of traditional Indian architecture useful in contemporary times?

The traditional Indian architecture involved fenestration to improve ventilation and lighting by letting the natural air and light inside any given space. However, the objective of fenestration has entirely changed in current times. Nowadays fenestration is aimed at increasing energy efficiency inside the space and reducing energy bills. While we still need the natural light to come inside the given space, we also need to maintain temperature inside the building/house. Advent of technology has enabled sustainable and green materials for this purpose which were not available in traditional times.

How has fenestration become an important factor in sustainable building design?

Fenestration has always been an integral part of any residential or commercial structure. Rising energy & material costs and sensitivity towards the environment have increased the importance of fenestration more than ever before. In addition to this, advancements in technology have facilitated materials which can help in reducing carbon emissions and increasing energy efficiency of the building, making it an important part of any construction.

What kind of fenestration is desired to reduce lighting and HVAC cost? What should be the corresponding R-value and U-value of the doors and windows being used?

Type of fenestration depends on the role and objective, for reducing the heat admitted into the building, glass with a lower solar heat gain coefficient (SHGC) should be used. If heat reduction is primary, we have to compromise on light transmission. Hence it is a tradeoff between the two characteristics and it is difficult to specify a certain number or percentage.

For reduction of heat, reflective, tinted and thicker glasses will help. Reflective glasses control solar heat by reflecting it outside. Tinted and thicker glasses absorb more heat but subsequently reradiate the heat outside. U-value is a non-solar heat measure and is the heat transfer coefficient. If the window system has low U-value, it will transmit less non-solar heat. R-value is the reciprocal of U-value, and a high R-value indicates less heat transmittance. While specifying a frame material (aluminum/UPVC) or glass (SGU/IGU/Laminate), it becomes necessary to prioritize between lighting, heat gain and acoustics.

When it comes to choosing uPVC or Aluminum windows for mass consumption properties and individual properties, what are some of the pointers to be kept in mind?

Due to their robust and easy usability nature, both uPVC and Aluminum have come up as preferred material for window and door needs in current times. However, the production, extrusion and installation of both these materials includes many technical aspects which end users might not be aware of. These technical aspects though not visible from outside, have huge impact on the longevity of the end product, hence it becomes important that these materials are purchased from a trusted and reliable vendor. Opting for end-to-end system integrators brings peace of mind for end consumers as these vendors take care of extrusion and installation along with warranty for their work done. Since these windows are highly customizable and durable, the application and purpose of window or door should be well thought in advance. For e.g., if prevention from mosquitoes is important then a separate track or panel should be planned for mesh shutter, glass configuration should be thought of in advance based on required energy efficiency inside the space etc.