The research described in this thesis consisted of the study of the concept of Planned Change, its application in diagnosing a particular problem, the implementation of a programme of planned change and its evaluation. The particular problem which gave rise to this research was the question of how to bring about a widespread increase in the efficient use of energy in local authority housing. This arose as a result of my membership of a small R & D group (SLCEG), working on local authority housing, where we had previously found that empirical evidence and rational argument was insufficient to encourage energy efficient housing design. The Concept of Planned Change offered an appropriate framework for investigating the problem as it is oriented towards improving social conditions through non-coercive means and provides for: identifying the various participants in the change process, diagnosis of the problem, setting goals and objectives, choosing strategies and designing a programme of activities and then monitoring their effect. Diagnosis of the problem identified that a multifaceted approach was required to solve the problem so that the design of the planned change programme included bringing about the formulation of an Energy Policy, creation of awareness of the benefits, practicality and affordability of energy efficient dwellings, identification and utilisation of leverage points and various other educational and facilitative activities. The Evaluation of the programme included both objective and subjective methods and indicated that a significant movement towards energy efficiency has been achieved but that adoption of this change is not evenly spread and that there are areas of resistance yet to be overcome. As a result of the evaluation, modifications to the programme of planned change were proposed which will include alterations to the exhibition, further educational activities - courses, workshops, etc. and wider dissemination of the energy savings achieved.