ABSTRACT
The preceding discussion demonstrates the possibility of achieving energy savings of up to 80 per cent in new residential and commercial buildings, relative to current practice in most countries. However, there is a large stock of existing, inefficient buildings. Our long-term ability to reduce energy use depends critically on the extent to which energy use in these buildings can be reduced when they are renovated. In Chapter 1, a rough criterion for sustainability of a factor of two to three reduction in the energy intensity of existing buildings was developed. In this chapter we show that reductions in the energy use of existing buildings of this magnitude are indeed possible.
