‘Housing for All by 2022’ is an ambitious initiative by the Government of India, to provide affordable and quality housing to the people of economically weaker sections (EWS) and the low-income group (LIG). Modular housing has become the de-facto in this context of low-cost and affordable housing. In this study, we evaluate the thermal comfort of a commercially available modular house with respect to different low-cost building wall materials and window glass panes. Dynamic energy simulations were carried out for Mumbai to analyse the thermal-comfort performance of such houses throughout the year. Results have shown that none of the low-cost building materials was competent enough to meet the ASHRAE-55 standards. However, a combination of glass fibre reinforced gypsum board and a blue-tinted glass of a 6mm thickness, performed better in thermal comfort in comparison to other materials. This study showed the need for the development of efficient low-cost building materials in order to address the long-term sustainability of the low-cost housing project.