Vernacular architecture is a term used to categorize methods of construction which use locally available methods and materials.it tends to evolve over time to reflect the environment and historical context in which it exists. Indian vernacular architecture is the functional architecture of structures, often in rural areas of India, built of local materials and designed to meet the needs of the local people vernacular architecture of Kerala is known for years for its climate-responsive design for a comfortable indoor environment. It is found to be highly effective in providing thermally comfortable indoors – a cool condition during summer and warmth in winter. The experimental investigations conducted so far reveals that the reason for thermal discomfort in the summer season in Kerala is not only due to the increase in temperature but also due to the increase in the moisture content in the air during the period. In Kerala vernacular architecture, this is achieved with a highly insulative building envelope, the presence of the internal courtyard provided within the living spaces and an optimum number of window openings on the external walls with suitable sizes. Vernacular architecture gives solutions that are in perfect harmony with nature.