Elements of good climatic design: Tripartite Windows

Windows are a building’s eyes to the world! The origin of the name ‘window’ in several languages can be traced to identify with the meaning ‘to let in wind and light’. Windows serve a fundamental role in architecture by connecting interior and exterior spaces. They allow natural light to enter, enable ventilation, offer views, and ensure privacy. In a building, while rooms are enclosures sheltered from the outside, windows make them habitable.

The design of windows is closely intertwined with the local climate, and various architectural solutions have emerged to address these functional needs.

If we examine vernacular architecture, we find a multitude of window and fenestration solutions, each unique to the microclimate it is located in. Be it the jaalis of northern India, the various types of wooden louvres in Kerala or Bengal, or the tiny and deep windows of the Himalayan settlements, the types of windows and fenestration solutions are as varied and diverse as the climatic conditions in which they are located. Therefore, the design of windows is closely related to the climate of the place. Let’s delve deeper into successful window designs that function best in our climate.

The Tripartite Window System

One of the most effective window solutions in hot and humid/dry climates is the ‘Tripartite Window System’ found in traditional pol houses of Ahmedabad. This type of window integrates all three functions of providing light, ventilation, and privacy. It is also adjustable so that the openings, light, and view can be changed based on different requirements.

A typical window is divided into three vertical zones. The upper zone incorporates a ventilator with glass to allow light and release accumulated hot air. The middle and lower zones are divided into 2 sets of openable shutters. The lower shutters can be kept open to allow cool air to enter. Furthermore, it brings in the breeze when one is seated close to the ground or lying on the floor. The upper zone provides light and views of the outside. These shutters can be operated independently, offering control over privacy, wind movement, and light, thus enhancing interior thermal comfort and atmosphere.

Similar concepts can be found in vernacular architecture in other regions. For instance, Chettinad houses in Tamil Nadu also employ a two-shutter division for windows. In some cases, adjustable louvres replace solid wooden panels, balancing sunlight and air circulation.

Benefits of tripartite windows:

The benefits of such window designs are notable where the adjustability of the components allows for a comfortable indoor environment, which in turn contributes to the energy efficiency of the building. In today’s context, where air conditioning often dominates interior comfort strategies, the significance of windows as climate control elements is often overlooked. Furthermore, in hot climates, the size, position, and number of windows also determine the amount of heat that enters the building.

Our approach

In the context of modern challenges like climate change¹, thoughtful approaches to design, from the overall concept to the materials used, as well as individual elements such as windows are becoming increasingly important. For our design of the Brick House², located in the southern region of Tamil Nadu we implemented several strategies regarding window openings to tackle the hot and humid climate of that place.

Brick House – Design of windows and openings to block heat and allow cool breeze inside

By incorporating a brick jaali in front of windows, the harsh sunlight is diffused, and incoming air is cooled. The window openings are divided into two zones – the top zones are made of glass which allows light to enter even when closed, while the lower zones are made of solid shutters which enable a cool breeze to flow naturally when open. The shutters are placed at a level such that the cool breeze is directed towards the seated person. The entire house is designed to function as a chimney, improving ventilation through the stack effect.

Finally…

We must relook at several elements of design whether it is the windows, the type of wall construction, materials, etc. to align our buildings with the local climate and needs. There is a wealth of inspiration available from vernacular architecture³ that can be re-adapted to our modern needs.