Why & how to implement passive design ideas in your home, architect Chitra Vishwanath explains

Gandhi Ashram is well-suited to Ahmedabad's dry, composite climate. The integration of water bodies and semi-open spaces allows cool air to flow through the building, while shade and the presence of water features help maintain a passive environment, says Chitra Vishwanath. (Image credit: Umar vis Wikimedia Commons 3.0)

Godrej Design Lab in Mumbai will host its second Conscious Collective event from December 13-15. On December 15, as part of the Conscious Collective 2024 conversation series, architects Veerendra Wakhloo (Matra Architects & Rurban Planners) and Chitra Vishwanath (Biome Environmental Solutions) will speak to Kaiwan Mehta of the Balwant Sheth School of Architecture about "Implementing passive design: India's sustainable future a belief or necessary practice". Ahead of the event, we asked Chitra Vishwanath to explain what passive design is, and how to use it in homes and other spaces. Excerpts from the email interaction:

What is passive design?

In response to your question, I would like to first define what I consider a public building: it is a structure funded by the government that is accessible to everyone.

The term "passive" is a contemporary concept. In the past, buildings had to be primarily passive because active cooling technologies were not readily available or were rarely used. Today, however, actively cooling a building is much easier. Passive design, therefore, focuses on keeping a building cool and usable without the reliance on air conditioning.

What do you consider to be an excellent example of passive design?

In many regions of India, effective passive strategies include shading and allowing air circulation around the body. A notable example of this is the Gandhi Ashram in Ahmedabad, designed by Charles Correa, which is one of my favorite buildings. It is well-suited to Ahmedabad's dry, composite climate, characterized by long summers and a brief rainy season, which means it doesn't experience extreme humidity. The integration of water bodies and semi-open spaces allows cool air to flow through the building, while shade and the presence of water features help maintain a passive environment.

Is it possible to build passive design solutions into existing homes and offices?

Retrofitting existing buildings for passive cooling can be achieved in various ways, provided there is enough space. Green roofs work exceptionally well in hot, dry climates, while shaded terraces are effective in hot, humid climates. Classic strategies, like shading windows from the outside, remain impactful. Additionally, a simple yet effective method is to avoid carpeting indoors and walk barefoot, which can help keep spaces cooler.