With rapid population growth and consequential urbanization, there have been concerns on environmental pollution and rapid depletion of natural resources. This has driven the construction industry to drift its practices from conventional to something sustainable. The reluctance in utilizing modern techniques, methods in construction, mediocre importance to sustainable materials, lack of knowledge and confidence in utilizing the industrial by-products at different stages of construction especially in the residential sector are some among many reasons for below-par success. The use of industrial by-products in scientific proportions, in fact not only contributes towards improving strength and durability aspects but also improves the thermal properties of the material leading to better comfort and lesser energy demand. The present study attempts to identify alternative concretes which are nothing but conventional concrete incorporated with supplementary cementitious materials and M-sand, evaluate for the strength parameters such as compressive strength, split tensile strength and flexural strength. Further, the study also aims to determine the thermal conductivity values for such alternative concretes using axial heat flow method and ascertain the effect of density on thermal conductivity values. The results are hence interpreted as a mean to choose the best material for construction that provides thermal comfort and reduce the energy consumption by improving energy efficiency of the building.