The focus of this paper is to assess the effect of building envelope on indoor climate control. Building envelope is a principal mediator between exterior and interior environmental conditions. The building envelope must respond to varied climatic conditions including extremes of temperature, solar radiation, precipitation and wind movement. The envelope may be required to act as a buffer, filter or concentrator medium at different times. Appropriate selection and manipulation of surface materials can control thermal and solar transmission. In most climates any attempt to ensure thermal comfort by passive means would reduce the active control requirements. In the cold climatic regions, or in the winter of temperature climatic regions, passive solar heating, good insulation and careful control of air infiltration would reduce the heating requirements. In a hot-dry climatic region, the massive walls evaporate cooling and good shading may succeed in ensuring comfort. A building is said to be climate modifier when it will: Provide comfort and healthy environment to the people inside the building, Reduce energy cost, and (III) Use “natural energy” instead of mechanical one. It has been found form numerous studies that the building envelope and built environment affect the microclimate of an area. The configuration of buildings, orientation, and their arrangement in space, create a specific microclimate for each site. To make the envelope more functional we can add specific building materials, surface textures and colours to exposed surfaces of buildings and the designs of open spaces such as streets, courtyards and gardens. These man made environments when interact with the natural microclimate such as light, heat, wind and humidity, can create comfort in the built environment. Defective design requires energy intensive mechanical means for their rectification.