The use of most of the computer programs available for energy analysis in buildings presents a somewhat formidable obstacle to the first time user. Frequently it takes so much time and effort to become familiar and competent with just one of these programs, that consideration is not freely given to other computer programs of a similar nature that mayor may not be better for the intended purpose.

The manner in which computer programs for energy analysis may be compared varies. Several programs may be compared by one user comparisons of results on one program may be made by several users or, several users may make comparisons with several programs for the same problem. The results obtained from these types of comparisons will frequently differ widely. The purpose of this paper is to present the results of two such comparisons to present some of the reasons why they agree or disagree and to draw some conclusions regarding the use of energy analysis computer programs. In order to protect the anonymity of the various users and computer program authors, no names are used in this paper. Nor are the specific magnitude of the results given. All data presented are shown relative to zero and toeach other. No attempt has been made to minimize or amplify the differences.