Please note that this is a scanned copy of a paper originally published in 1990, so the text is not as clear as in documents created as pdf files.

This Digest identifies the factors determining energy requirements (Figure 1 shows the energy flows into and out of a typical house) and describes the methods used to assess energy efficiency. The levels of energy efficiency required for new dwellings by the Building Regulations [1990 edition] are discussed. It considers improvements to the efficiency of existing buildings, taking account of the opportunities that arise when major refurbishments are carried out.