In the last few decades , the environmentally friendly or sustainable house has been associated with green enthusiasts who built homes to both blend in with the natural landscape and harness renewable energy resources . As we enter the new millennium environmental concerns will become a matter of expediency . Architets , developers , and homeowners will be pressed to take a more pragmatic approach to where they build , and the more economic use of space and energy supplies . Extremeclimates currently present archiets with the greatest challenge in energy conservation in. In urban areas , there is a growing trend for disused buildings that can be converted into housing and for dwellings that can be easily adapted to accommodate different types of resident .