Centre for Advanced Research in Building Science and Energy (CARBSE) at CEPT University has developed a wall and roof construction thermal transmittance or thermal Conductance (U – Factor) calculator. This is an online tool, to be accessed freely over internet. The values derived by the tool are specific for the city. Thermal properties of materials used by the tool are derived by extensive characterization of generic construction materials available in various parts of India at CARBSE, CEPT University. The tool can be used for selection of building material, construction, for building energy modelling and analysis as well as for code compliance. This tool is supported by Ministry of New and Renewable Energy, Govt. of India and Shakti Sustainable Energy Foundation, India.