Exploring the time dimension of low carbon retrofit: Owner-occupied housing

Low carbon housing retrofit is often understood as a one-off, whole-house activity. However, an alternative model of low carbon retrofit is presented whereby improvements happen step by step over several years. This staged approach is described and contrasted with the one-off approach, and empirical evidence on both models is presented. Three key questions are considered: whether an over-time low carbon retrofit could be attractive for owner-occupiers; whether it could deliver sufficient carbon and energy savings; and what policy support would be needed. The benefits of over-time low carbon retrofit are explored through householder survey and qualitative data, as well as the time scales that apply to housing, renovation and homeowners. Technical issues around energy savings are explored, and the risks of lock out investigated. Policy support measures specifically for over-time low carbon retrofit are suggested, with reference to existing policy approaches in the United Kingdom and European Union. Over-time low carbon retrofit could be attractive to (some) householders - at least 60% carbon savings could be achieved - and policy could be designed to recognize and support this form of low carbon retrofit. This approach provides an additional route to the uptake of energy-efficiency and renewable-energy measures.