Energy program validation: conclusions of IEA Annex 1.

States that the calculation of building energy flow is very complex, and so validation is a vital element in the development of any model. Describes an IEA R and D project to compare 23 computer programs (from 8 different countries) both in terms of consistency between programs, and in thei relative accuracy in modelling the behaviour of a real building (the Avonbank office block in Bristol). Summarizes the major conclusions developing out of the project and discusses the most important aspects which need to be considered in the development of a reliable computer program.